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A mes parents, Pierre et Dominique Machery
Acknowledgments
This won’t surprise you if you’re already an author: It takes a village to write a book, and authors take on so many debts that it may be more convenient to pretend to be an intellectual island. But I won’t travel that path, acknowledging instead my many debts. The impetus for this book comes from an invitation by Michael Strevens and David Chalmers to present some work in the Mind and Language seminar they organized at NYU in 2013. The shortcomings of my presentation convinced me of the need to write a book on the topic. I thought the book would be sweet and short, but sometimes reality bites, and a longer, more detailed treatment ended up being necessary.
Many philosophers have generously taken the time to comment on older versions of this book, and I have extensively benefited from their generosity. Students, colleagues, and visitors at Pitt suffered through the first version of the manuscript in a reading group at the end of 2014, and their feedback was extraordinary: Thanks to Mikio Akagi, Joshua Alexander, Jim Bogen, David Colaço, Matteo Colombo, Taku Iwatsuki, Joe McCaffrey, Jasmin Özel, Alison Springle, and Zina Ward. Many thanks too to the participants to the reading group at Washington University during my semester-long visit in the winter of 2015: Mike Dacey, Eric Hochstein, Anya Plutynski, Felipe Romero, Rick Shang, Brian Talbot, and Tomek Wisocky. I am particularly grateful to Brian Talbot, who raised challenging objections for each of the chapters. Mark Sprevak organized a seminar meeting on a version of Chapter 3 during my visit at Edinburgh in 2014 and, again, a reading group on the whole book in 2016. The discussion of Chapter 3 with Mikkel Gerken, Michela Massimi, Andrea Polionoli, Stephen Ryan, and Mark Sprevak led me to rewrite this chapter entirely (thanks guys!). I have also been thinking about, and sometimes struggling with, the comments from the 2016 reading group for months: Thanks to Ian Bisset, Jesper Kallestrup, Stephen Ryan, Rick Sendelbeck, Mark Sprevak, Orestis Spyridon, and Annie Webster. Sascha Benjamin Fink organized a wonderful one-day workshop on the book manuscript at the Berlin School of Brain and Mind during the fall of 2015. Thanks to all the participants: in addition to Sascha Benjamin Fink himself, Raphael Becker, Dimitri Coelho Mollo, Matthijs Endt, Ramiro Glauer, Markus Hoffmann, Rhea Holzer, Joachim Horvath, Lena Kästner, Juan R. Loaiza, Stephan Pohl, and Lara Pourabdolrahim. Corinne Bloch Mullins organized a reading group at Marquette and sent me some comments resulting from the participants’ discussion. Thanks to the participants to this reading group, including Yoon Choi, Anthony Peressini, and Margaret Walker. Wesley Buckwalter wrote some detailed feedback on Chapter 4 and Joe Milburn on Chapters 1 and 3; Jennifer Nagel made some helpful remarks about Chapter 1. Stefano Cossara read the near final version of the whole book and helped me reformulate some key claims. Thanks for the detailed, sympathetic feedback from the two anonymous reviewers for
Oxford University Press: One only wishes all reviewers were as smart and understanding. Finally, many thanks to John Doris, who met with me on a weekly basis over breakfast to discuss each chapter during my semester-long visit at Washington University: These meetings were one of the intellectual (and gastronomical) highlights of my visit!
Other philosophers have given me feedback on particular claims or arguments in the book. I consulted with Eric Hatleback, Peter Machamer, Paolo Palmieri, and Elay Shech for the history-of-science examples discussed in Chapter 3. My colleagues in the Department of History and Philosophy of Science at the University of Pittsburgh also responded to my request for examples of scientific instruments lacking calibration and hopefulness. Facebook hivemind was put to contribution for issues related to the literature on disagreement discussed in Chapter 4: Thanks to Endre Begby, Carlo Martini, Andrés Páez, Darrell Rowbottom, and Greg Wheeler for answering my questions. My email exchange with John Turri helped me better understand his criticisms of the Gettier cases written by philosophers. Michael Strevens had searching questions about Chapter 7 and its relation with Doing without Concepts.
I have given many talks based on the materials of this book. I’d like to single out an early lecture as well as an informal seminar meeting at Syracuse generously organized by Kevan Edwards and the keynote lecture at the UK conference in experimental philosophy in Nottingham during the summer of 2015.
Steve Stich’s fingerprints are all over this book, as will be apparent to many. I am delighted to have yet another occasion to acknowledge my intellectual debts! My family was a source of joy and sorrow while writing this book: My father, Pierre, passed away, and my daughter, Uliana, was born. I dedicate this book to my parents, Pierre and Dominique Machery.
List of Figures
2.1 Percentages of Kripkean judgments in Gödel cases (based on Machery et al., 2004; Beebe & Undercoffer, 2015, 2016; Machery et al., 2010; Machery et al., 2015; Sytsma et al., 2015) 49
2.2 Percentages of Kripkean judgments in two Jonah cases (based on Beebe & Undercoffer, 2016) 51
2.3 Percentages of Kripkean judgments (based on Machery et al., 2009) 52
2.4 Percentages of knowledge ascriptions (based on Weinberg et al., 2001) 53
2.5 Percentages of knowledge denials for two Gettier cases, a clear knowledge case, and a false belief case (based on Machery et al., forthcoming a) 55
2.6 Means of knowledge ascriptions in skeptical-pressure cases (based on Study 2 of Waterman et al., forthcoming) 55
2.7 Percentages of permissibility judgments (based on Hauser et al., 2007) 56
2.8 Percentages of “should” judgments (based on Ahlenius & Tännsjö, 2012) 57
2.9 Percentages of “appropriate” judgments in the footbridge case (Xiang, 2014) 58
2.10 Percentages of incompatibilist judgments (based on Sarkissian et al., 2010) 58
2.11 Percentages of “intentional” judgments (based on Knobe & Burra, 2006) 59
2.12 Mean judgments in four cases (based on Buckwalter & Stich, 2015) 61
2.13 Percentages of knowledge ascriptions in a Truetemp case (based on Wright, 2010) 71
2.14 Percentages of knowledge ascriptions in a fake-barn case (based on Wright, 2010) 71
2.15 Percentages of knowledge denials in a Gettier case (based on Machery et al., forthcoming b) 72
2.16 Mean intentionality judgments in the harm and help cases (based on Feltz & Cokely, 2011) 74
2.17 Percentages of knowledge denials for two Gettier cases (based on Machery et al., forthcoming b) 78
2.18 Mean knowledge ascriptions in Gettier cases (based on Buckwalter, 2014) 80
2.19 Mean knowledge ascriptions in lottery-style cases (based on Turri & Friedman, 2014) 80
2.20 Percentages of “remain in the experience machine” judgments (based on De Brigard, 2010) 84
2.21 Mean judgments in the harm case in the first- and third-person conditions (based on Feltz et al., 2012) 84
7.1 Proportion of the variance independently predicted by fixity, typicality, and teleology (based on Study 1 of Griffiths et al., 2009) 243
If we find those who are engaged in metaphysical pursuits, unable to come to an understanding as to the method which they ought to follow; if we find them, after the most elaborate preparations, invariably brought to a stand before the goal is reached, and compelled to retrace their steps and strike into fresh paths, we may then feel quite sure that they are far from having attained to the certainty of scientific progress and may rather be said to be merely groping about in the dark. In these circumstances we shall render an important service to reason if we succeed in simply indicating the path along which it must travel, in order to arrive at any results—even if it should be found necessary to abandon many of those aims which, without reflection, have been proposed for its attainment.
Kant, Critique of Pure Reason, Preface to the Second Edition
Introduction
There are people around who have Very Strong Views (“modal intuitions,” these views are called) about whether there could be cats in a world in which all the domestic felines are Martian robots, and whether there could be Homer in a world where nobody wrote the Odyssey or the Iliad. Ducky for them; their epistemic condition is enviable, but I don’t myself aspire to it.
(Fodor, Psychosemantics, p. 16)
The aim of Philosophy Within Its Proper Bounds is simple, albeit ambitious, arrogant some may say: curbing philosophers’ flights of fancy and reorienting philosophy toward more humble, but ultimately more important intellectual endeavors. I argue that resolving many traditional and contemporary philosophical issues is beyond our epistemic reach: We cannot know whether dualism is true (supposing that actual psychological events happen to be physical events), whether pain is identical to some complicated neural state (supposing that actual pains are identical to neural states), what knowledge really is, what makes an action morally permissible, whether causation just is some relation of counterfactual dependence between events, whether I remain the same person because of the continuity of the self, and whether necessarily an action is free only if the agent could have acted otherwise. These philosophical issues and similar ones should be dismissed, I conclude.
This conclusion may seem dire, and I expect serious pushback from philosophers, but it is in fact cause for rejoicing: There are important issues in the neighborhood of most of the dismissed philosophical issues, and these are within our epistemic reach. Even if we cannot know whether pain is identical to some neural state, supposing facts about the actual world do not settle the issue, we can still learn whether according to our best science pain is identical to a neural state. Even if we cannot know whether causation can be identified with a relation of counterfactual dependence, we can still understand the properties that are characteristic of causal relations in a large range of actual systems, and we can understand why scientists proceed as they do to establish causal claims. Equally important, the dismissal of such philosophical issues would free time and resources for bringing back to prominence a once-central intellectual endeavor: conceptual analysis. In recent years, conceptual analysis has unfortunately been associated with the search for analytic truths and a priori knowledge, but this
conception is too narrow, and overlooks the traditional goals of conceptual analysis: clarifying and assessing ideas.
Resolving many traditional and contemporary philosophical issues requires some modal knowledge (i.e., knowledge about what is necessary and possible). Typically, epistemologists are not after what knowledge is like in the actual world; they have little to say about its contingent properties—those properties knowledge has, but would not if the world were different. They are not even after what knowledge is like for creatures like us, for creatures obeying the laws of nature; they have little to say about what promotes or hinders knowledge for minds like us—minds obeying the same psychological laws—and more generally about the net of causal laws knowledge is embedded in (Bishop & Trout, 2005). No, what philosophers are after is what knowledge must be, what knowledge is, or at least requires, in every possible world. Similarly, most moral philosophers do not want to explain what makes something morally permissible in the actual world or for creatures with our psychology; they are after what permissibility must be. Philosophers too rarely debate what free will and responsibility would be for minds constituted like ours; rather, they are usually concerned with, e.g., whether necessarily an action is free only if the agent could have acted otherwise or whether necessarily an agent is responsible for her action only if she is the source of her action. Resolving many central issues in the history of philosophy and in contemporary philosophy also turns on knowing what would be the case in situations utterly different from those governed by the laws of nature. If physicalism is true, necessarily every psychological event is a physical event, and you could not have a physical duplicate that would not also be a psychological duplicate, but if dualism is true, there could be physical duplicates that are not psychological duplicates, something that could probably only happen if the laws of nature did not hold. If type identity theory is true, every psychological property is a physical property, and the instantiation of a psychological property must be identical to the instantiation of one and the same physical property, but if the multiple realizability hypothesis is true, two instantiations of a single psychological property could be identical to the instantiations of two distinct physical properties. Thus, the truth of the multiple realizability hypothesis does not depend only on the actual relation between psychological and physical properties, and instead of trying to disentangle what science tells us about the relations between psychological and physical properties, it may seem more expedient to attempt to determine how they could be related if the world were very different from the world described by science.
Such philosophical concerns, theories, and issues are modally immodest: Addressing them requires epistemic access to metaphysical possibilities and necessities. One of the main aims of this book is to defend a form of modal skepticism: While there may be such facts, I will argue that we cannot know many of the metaphysical possibilities and necessities of philosophical interest. And if we can’t, then modally immodest issues cannot be resolved, and modally immodest philosophical views supported.
The reader will need to follow me through an extensive detour to reach this modal skepticism. Much of the book assesses the main philosophical method for identifying the modal facts bearing on modally immodest philosophical views: the method of cases. Philosophers rely on the method of cases when they consider actual or hypothetical situations (described by cases) and determine what facts hold in these situations. These facts then bear, more or less directly, on competing philosophical views.
The method of cases has a long, prestigious history, and it is arguably already used by Plato: The Ring of Gyges story in The Republic is a plausible example. It is so important in contemporary philosophy that I could probably fill a whole book by quoting philosophical cases (e.g., Tittle, 2005), and even if I limited myself to the most famous and influential cases, I could perhaps cite a few dozen cases. Admittedly, it is used more often in some areas of philosophy than others. As a first approximation, the more naturalistic the research area, the less frequently it is used. It is rarely used in the philosophy of biology or in the philosophy of cognitive science, and it is uncommon (though occasionally used) in the philosophy of science. It is commonly used in epistemology, in some areas of the philosophy of language, and in ethics.
Consider Gettier’s (1963) classic article, which describes several cases in order to undermine the Justified-True-Belief analysis of knowledge he claims to find in Plato. “Case I” reads as follows (1963, 122):
Suppose that Smith and Jones have applied for a certain job. And suppose that Smith has strong evidence for the following conjunctive proposition:
(d) Jones is the man who will get the job, and Jones has ten coins in his pocket.
Smith’s evidence for (d) might be that the president of the company assured him that Jones would in the end be selected, and that he, Smith, had counted the coins in Jones’s pocket ten minutes ago.
Proposition (d) entails:
(e) The man who will get the job has ten coins in his pocket.
Let us suppose that Smith sees the entailment from (d) to (e), and accepts (e) on the grounds of (d), for which he has strong evidence. In this case, Smith is clearly justified in believing that (e) is true. But imagine, further, that unknown to Smith, he himself, not Jones, will get the job. And, also, unknown to Smith, he himself has ten coins in his pocket. Proposition (e) is then true, though proposition (d), from which Smith inferred (e), is false. In our example, then, all of the following are true: (i) (e) is true, (ii) Smith believes that (e) is true, and (iii) Smith is justified in believing that (e) is true. But it is equally clear that Smith does not know that (e) is true; for (e) is true in virtue of the number of coins in Smith’s pocket, while Smith does not know how many coins are in Smith’s pocket, and bases his belief in (e) on a count of the coins in Jones’s pocket, whom he falsely believes to be the man who will get the job.
Gettier concludes that it is not the case that necessarily someone knows that p if and only if she has a justified true belief that p.
Dretske’s cleverly disguised zebra case plays an important role in the assessment of the closure of knowledge under known entailment. He describes the case as follows (1970, 105–6):
Let me give you another example—a silly one, but no more silly than a great number of skeptical arguments with which we are all familiar. You take your son to the zoo, see several zebras, and, when questioned by your son, tell him they are zebras. Do you know they are zebras? Well, most of us would have little hesitation in saying that we did know this. We know what zebras look like, and, besides, this is the city zoo and the animals are in a pen clearly marked “Zebras.” Yet, something’s being a zebra implies that it is not a mule and, in particular, not a mule cleverly disguised by the zoo authorities to look like a zebra. Do you know that these animals are not mules cleverly disguised by the zoo authorities to look like zebras? If you are tempted to say “Yes” to this question, think a moment about what reasons you have, what evidence you can produce in favor of this claim. The evidence you had for thinking them zebras has been effectively neutralized, since it does not count toward their not being mules cleverly disguised to look like zebras. Have you checked with the zoo authorities? Did you examine the animals closely enough to detect such a fraud? You might do this, of course, but in most cases you do nothing of the kind. You have some general uniformities on which you rely, regularities to which you give expression by such remarks as, “That isn’t very likely” or “Why should the zoo authorities do that?” Granted, the hypothesis (if we may call it that) is not very plausible, given what we know about people and zoos. But the question here is not whether this alternative is plausible, not whether it is more or less plausible than that there are real zebras in the pen, but whether you know that this alternative hypothesis is false. I don’t think you do. In this, I agree with the skeptic.
But since according to Dretske we would know in this situation that zebras are in the cage, knowledge is not closed under known entailment: It is not the case that necessarily if I know that p and that p entails q, then I know that q
To show that someone’s right to life does not necessarily trump someone else’s right “to decide what happens in and to her body,” Thomson describes the famous society of music lovers case (1971, 49):
[N]ow let me ask you to imagine this. You wake up in the morning and find yourself back to back in bed with an unconscious violinist. A famous unconscious violinist. He has been found to have a fatal kidney ailment, and the Society of Music Lovers has canvassed all the available medical records and found that you alone have the right blood type to help. They have therefore kidnapped you, and last night the violinist’s circulatory system was plugged into yours, so that your kidneys can be used to extract poisons from his blood as well as your own. The director of the hospital now tells you, “Look, we’re sorry the Society of Music Lovers did this to you—we would never have permitted it if we had known. But still, they did it, and the violinist now is plugged into you. To unplug you would be to kill him. But never mind, it’s only for nine months. By then he will have recovered from his ailment, and can safely be unplugged from you.” Is it morally incumbent on you to accede to this situation? No doubt it would be very nice of you if you did, a great kindness. But do you have to accede to it? What if it were not nine months, but nine years? Or longer still? What if the director of the hospital says, “Tough luck, I agree, but you’ve now got to stay in bed, with the violinist plugged into you, for the rest of your life. Because remember this. All persons have a right to life, and violinists are persons. Granted you
have a right to decide what happens in and to your body, but a person’s right to life outweighs your right to decide what happens in and to your body. So you cannot ever be unplugged from him.” I imagine you would regard this as outrageous, which suggests that something really is wrong with that plausible-sounding argument I mentioned a moment ago.
Some doubt that the method of cases really plays a central role in philosophy. We will see in Chapter 6 that there is really no alternative to this method for assessing philosophically immodest theories, but for the time being I’d like to show that, as a matter of fact, philosophers do rely on the method of cases.
Cases play a central role in many classic articles. To give only a few examples in epistemology, applied and normative ethics, action theory, philosophy of language, and philosophy of mind, all the following classics include cases (with their citation numbers in parentheses1): Gettier’s “Is justified true belief knowledge?” (2453), Goldman’s “Discrimination and perceptual knowledge” (899), BonJour’s “Externalist theories of empirical knowledge” (318), Dretske’s “Epistemic operators” (805), Thomson’s “A defense of abortion” (1363), Thomson’s “Double effect, triple effect and the trolley problem: Squaring the circle in looping cases” (586), Frankfurt’s “Alternate possibilities and moral responsibility” (1265), Evans’s “The causal theory of names” (543), Block’s “Troubles with functionalism” (1361), Jackson’s “What Mary didn’t know” (967), and Searle’s “Minds, brains, and programs” (4667). Furthermore, not only do these influential articles include cases, the facts assumed to hold in the situations described by these cases also play a central role in the arguments they develop. Relatedly, cases guide the historical development of the relevant areas of philosophy. Gettier’s (1963) cases gave rise to the introduction of new conditions on justification and to the search for a fourth necessary condition in the analysis of knowledge. Proposals were assessed, and rejected, by means of further cases (for review, see Shope, 1983). BonJour’s clairvoyant case and Lehrer’s Truetemp case figure prominently in the discussion of reliabilism, as Goldman’s (2008) entry in the Stanford Encyclopedia of Philosophy shows:
The second objection is that reliability isn’t sufficient for justification. The principal example of this kind is due to Laurence BonJour (1980). . . . If someone disagrees with BonJour about the Norman case, there are other examples with similar contours in the literature that may be more persuasive. Keith Lehrer (1990) gives the case of Mr. Truetemp
Foot’s and Thomson’s trolley cases have framed the debate about the nature of moral permissibility. Searle’s Chinese room case is the basis of a classic objection against Strong AI.
Cases do seem to play an important role in philosophical argumentation; why, then, are some philosophers inclined to deny it? Some philosophers may confuse the proposed importance of the method of cases in philosophy with the claims that cases
1 From Google Scholar (August 12, 2015).
elicit “intuitions” and that these intuitions, however understood, are what ultimately justify philosophical views. However, the intuition-based characterization of the method of cases is one of the mischaracterizations I take on at the beginning of this book. Generally, the minimalist characterization of the method of cases I will offer has no truck with intuitions, epistemic or metaphysical analyticity, or conceptual competence. Some philosophers may respond that, if cases play a role in philosophy, it is a small one. In a sense, their role is indeed limited. The facts assumed to hold in the situations described by cases must be brought to bear on philosophical conclusions (about free will, meaning, moral permissibility, or causation), and doing this often requires long chains of reasoning. Much of philosophers’ ingenuity goes into developing these long chains of reasoning. Acknowledging this point is, however, consistent with the claim that, if we did not know which facts hold in the situations described by philosophical cases, we would not be able to draw the philosophical conclusions we hope to draw.
Perhaps by saying that cases play at best a small role in philosophy, some philosophers mean that other methods are available to reach the same conclusions. I’ll challenge this idea toward the end of this book (Chapter 6).
In any case, the first five chapters of Philosophy Within Its Proper Bounds examine whether we know or can come to know which facts hold in the situations described by philosophical cases. Can we really assume that Smith does not know that “the man who will get the job has ten coins in his pocket” in the situation described by Gettier’s Case I? That Truetemp does not know that “the temperature is 104 degrees” in the situation described by Lehrer’s case? That it is really impermissible to push the large person in the situation described by Thomson’s footbridge version of the trolley case? That Frankfurt cases describe free actions? The present book makes a case for a negative answer. We are not entitled to assume that it is really impermissible to push the large person in the situation described by Thomson’s case and that Truetemp does not know the temperature, and we should not bring the alleged facts to bear on philosophical views: Our theory of knowledge cannot be built on the facts often assumed to hold in Gettier cases or in the Truetemp case, and a theory of moral permissibility cannot be built on the facts often assumed to hold in the situations described by trolley cases. And so on, I argue, for most philosophical cases.
Fifteen years of experimental research on the judgments elicited by philosophical cases show that these are often “cognitive artifacts”: They reflect the flaws of our “cognitive instruments,” exactly as experimental artifacts reflect the flaws of scientific instruments. Philosophical cases also tend to elicit different responses: If these responses are a genuine sign of disagreement, we ought to take stock of this disagreement by suspending judgment; if these responses indicate instead that people are speaking at cross purposes, then we should reorient our research priorities and at least for the time being stop theorizing about justice, permissibility, causation, or personal identity.
Philosophers have of course sometimes expressed concerns about the judgments elicited by philosophical cases. Some cases, for instance, have long been known to elicit contradictory judgments when framed differently. Williams (1970) created two
cases that elicit contradictory judgments about personal identity and concluded (1970, 168–9),
[T]he whole question [personal identity] seems now to be totally mysterious. For what we have just been through is of course merely one side, differently represented, of the transaction which we considered before; and it represents it as a perfectly hateful prospect, while the previous considerations represented it as something one should rationally, perhaps even cheerfully, choose out of the options there presented. It is differently presented, of course, and in two notable respects; but when we look at these two differences of presentation, can we really convince ourselves that the second presentation is wrong or misleading, thus leaving the road open to the first version which at the time seemed so convincing? Surely not.
Lewis (1986, 203) identified a pair of cases that could not be used to constrain philosophical theorizing about causation because they were “far-fetched”; rather, the theories developed in part on the basis of other cases would determine what to think about the cases: “I do not worry about either of these far-fetched cases. They both go against what we take to be the ways of this world; they violate the presuppositions of our habits of thought; it would be no surprise if our commonsense judgments about them went astray—spoils to the victor!” More recently, Gendler and Hawthorne (2005) have also noted that different formulations of the fake-barn case lead to different judgments.2 Philosophers have typically limited their concerns to specific cases, but similar concerns apply in fact much more widely. And if one is convinced by Williams’s discussion of personal identity or Gendler and Hawthorne’s discussion of fake-barn cases, one should have concerns about most philosophical cases.
I conclude from the discussion of the method of cases that we should suspend judgment in response to most philosophical cases. This radical conclusion is at odds with a more common view among critics of the method of cases: moderate restrictionism (Alexander & Weinberg, 2007; Weinberg, 2007; Alexander, 2012). A moderate restrictionist “advocates not the root and branch removal of all intuitions, but just the pruning away of some of the more poisoned philosophical branches” (Alexander & Weinberg, 2007, 16). Moderate restrictionists hold that a substantial number of cases elicit reliable judgments and they are hopeful that, perhaps with the help of experimental philosophy, we may be able to identify the class of safe-for-thinking cases. By contrast, according to the radical restrictionism defended in Philosophy Within Its Proper Bounds, we ought to suspend judgment in response to not only most current philosophical cases, but also the type of actual and possible cases that would be most useful for philosophizing about modally immodest philosophical issues.
It is important to be crystal clear about the content of radical restrictionism. It is not a skepticism about judgment in general or, more narrowly, about the judgments concerning the topics of philosophical interest—e.g., knowledge, causation, permissibility, or personal identity. We are pretty good at distinguishing ignoramuses from
2 See also Unger (1996, e.g., on Trolley cases pp. 88ff.); Gendler (2007); Norcross (2008).
people who know what they are talking about; we often have no trouble recognizing causes; and we typically know which actions are morally permissible and which are not. Nor is radical restrictionism a skepticism about judgments elicited by texts: We do not need to meet politicians to know that many of them do not know what they are talking about—reading about them is often enough—and moral judgments about war crimes read in the New York Times are not under suspicion. Radical restrictionism has a narrower scope: It focuses on judgments elicited by a particular kind of text, namely the kind of case philosophers tend to use to support modally immodest philosophical views. Judgments elicited by other texts are not under suspicion, and indeed I’ll be using a few cases of this second type in the book.
Also radical restrictionism isn’t a form of eliminativism about the use of cases in philosophy. Cases are used for very different purposes in philosophy (Chapter 1), many of which are perfectly acceptable and will not be the focus of this book. Some of the uses that are discussed in the coming chapters are also beyond criticism: In particular, I will defend a version of conceptual analysis (Chapter 7), recommending the use of judgments about a particular type of case to study concepts of philosophical interest. Even the use of cases to answer questions such as, What is knowledge? or What does causation reduce to?, which will be the focus of much of this book, can be appropriate in some restricted circumstances. Judgments about everyday cases will not be impugned, although it is not clear how much philosophical mileage one can gain from them (Chapter 3). Finally, philosophical cases that are known to elicit consensual, unbiased judgments, if there are any, can remain in our toolbox for philosophizing.
End of the detour: Radical restrictionism undercuts modally immodest philosophical views. These views assume that we have epistemic access to the facts that hold in the situations described by cases, but we don’t. We should thus abandon the hope of resolving modally immodest philosophical issues; we are unable to determine what knowledge, moral permissibility, and causation essentially are; if facts about the world do not settle the question of dualism, then we are not in a position to know whether dualism is true.
We are now free to redirect our attention toward issues that do not require some epistemic access we can’t have. Of prime importance is the descriptive and prescriptive analysis of concepts. Conceptual analysis has bad press in contemporary philosophy, including among naturalistic philosophers whose work is most congenial to mine, but it is time to reassess its prospects. The vices of some particular, though influential conceptions of conceptual analysis do not generalize to the naturalized conceptual analysis defended in Philosophy Within Its Proper Bounds. And this form of conceptual analysis is philosophically important. It allows us to better understand ourselves and to improve the inferences we are prone to draw, and it enables us to square the world of common sense with that of science.
Finally, some may suspect that philosophizing about philosophy is a sign of philosophy’s loss of vigor: Only declining fields become introspective. This suspicion
is, however, misplaced. Without going as far as Sellars (1963, 3), according to whom, “It is this reflection on the place of philosophy itself in the scheme of things which is the distinctive trait of the philosopher as contrasted with the reflective specialist; and in the absence of this critical reflection on the philosophical enterprise, one is at best but a potential philosopher,” philosophizing about the nature, goals, methods, and limitations of philosophy has always been part of the philosophical activity. Plato, Hume, Kant, Nietzsche, Marx, and Carnap, to give only a few examples, extensively philosophized about philosophy, and nearly every decade of the second half of the twentieth century witnessed intense, multifarious metaphilosophical debates: To allude to only some of these debates, philosophers involved in the linguistic turn extensively debated whether, and in which sense, philosophical questions were linguistic questions; the 1950s and 1960s saw scores of articles pitting the metaphilosophy of ordinary language philosophy against that of Carnap and his followers; the 1960s addressed the concerns raised by Fodor and others against ordinary language philosophy; in the 1960s, 1970s, and the 1980s philosophers of science debated the role of the history of science in the philosophy of science; the 1970s examined the prospects of reflective equilibrium; the 1980s were in part concerned with the naturalization of philosophy; the 1990s with mysterianism and with the Canberra plan and its offshoots; the 2000s with the relation between conceivability and possibility and with the significance of experimental philosophy. Dig a bit in a period of philosophy, and you’ll find some active philosophy of philosophy going on.
The chapters of Philosophy Within Its Proper Bounds develop the themes broached in this introduction in a systematic manner.
Chapter 1,“The Method of Cases,” compares three characterizations of the method of cases: exceptionalist, particularist, and minimalist characterizations. Among the most prominent exceptionalist characterizations are those that characterize the attitudes elicited by cases as expressing a conceptual competence, as epistemically analytic, as metaphysically analytic, or as irreducible intuitions. Among the most prominent particularist characterizations are those that characterize these attitudes as obvious or spontaneous judgments. Chapter 1 shows that only a minimalist characterization, according to which cases elicit everyday judgments, is philosophically adequate—it does not rely on empty notions or on notions useless to characterize the method of cases—and descriptively adequate—it captures how philosophers really use cases.
Chapter 2, “The Empirical Findings,” is the first systematic review of the empirical findings suggesting that the judgments influenced by cases vary across demographic groups and are influenced by the way cases are presented. Nearly every examined case, from nearly every area of philosophy, elicits judgments varying across demographic groups or different judgments depending on how the case is presented.
Chapter 3, “Fooled by Cognitive Artifacts,” examines one of the two concerns often brought up against the method of cases: The judgments elicited by cases seem
epistemically deficient. This concern is captured by the first argument against the method of cases, which I call “Unreliability”: Cases currently used in philosophy as well as those cases that would be particularly useful for some central philosophical purposes are likely to elicit unreliable judgments. I conclude that we ought to suspend judgment.
Chapter 4, “Enshrining Our Prejudices,” builds upon the second concern often brought against the method of cases: People make different judgments in response to cases. Chapter 4 develops a dilemma against the method of cases: If people are genuinely disagreeing, then according to the most important views in the epistemological literature on disagreement we ought to suspend judgment in response to cases; if people are in fact talking at cross purposes, then we should reorient our research priorities; instead of theorizing about what our judgments refer to, we should first decide what is worth theorizing about—the objects of our judgments or the objects of their judgments. Both arguments, Dogmatism and Parochialism, lead to the same conclusion: We should shelve the method of cases.
Chapter 5, “Eight Defenses of the Method of Cases,” examines eight different ways of defending the method of cases against Unreliability, Dogmatism, and Parochialism, and finds them wanting. I defend the experimental bona fides of experimental philosophy, provide evidence that reflective judgments do not differ from the judgments reported by experimental philosophers, show that philosophers are not expert judgers, explain why their findings generalize beyond the cases that have been examined, argue that the lesson to be drawn from experimental philosophy can’t just be that judgments are fallible, explain why the prospects for a reform of the method of cases are dim, make the point that Unreliability, Dogmatism, and Parochialism do not rest on a mischaracterization of the use of cases in philosophy, and defuse the threat that if sound these three arguments would justify an unacceptable general skepticism about judgment.
Chapter 6, “Modal Ignorance and the Limits of Philosophy,” examines the implications of Unreliability, Dogmatism, and Parochialism for modally immodest philosophizing: Modally immodest issues should be dismissed. Alternatives to the method of cases are critically examined: We cannot gain the required modal knowledge by relying on intuition, by analyzing the meaning of philosophically significant words, and by appealing to alleged theoretical virtues like simplicity, generality, and elegance to choose between philosophical views.
Chapter 7, “Conceptual Analysis Rebooted,” proposes a new, naturalistic characterization of conceptual analysis, defends its philosophical significance, and shows that usual concerns with conceptual analysis do not apply to this revamped version. Furthermore, naturalized conceptual analysis often requires empirical tools to be pursued successfully, and an experimental method of cases 2.0 should often replace the traditional use of cases in philosophy.
The Method of Cases
Let’s suppose, then, that there were two such rings, one worn by the just person, the other by the unjust. Now no one, it seems, would be so incorruptible that he would stay on the path of justice And in so behaving, he would do no differently than the unjust person, but both would pursue the same course. This, some would say, is strong evidence that no one is just willingly, but only when compelled.
Plato, Republic (Book 2, 360 b–d)
The first chapter of Philosophy Within Its Proper Bounds defends a particular characterization of the method of cases and identifies some of the roles it plays in contemporary philosophy. In Section 1.1, I examine how cases are used in philosophy. In Section 1.2, I contrast exceptionalist, particularist, and minimalist characterizations of the method of cases, and I embrace a minimalist characterization. In Section 1.3, I show that the main exceptionalist characterizations are philosophically inadequate: They rely on notions that are either empty or useless to characterize the method of cases. In Section 1.4, I further argue that only the minimalist characterizations of the method of cases are descriptively adequate: Exceptionalist and particularist characterizations do not describe correctly how philosophers use cases.
1.1 The Method of Cases
1.1.1 Philosophical cases
Cases are descriptions of actual or hypothetical situations, and philosophical cases are cases put forward by philosophers. Philosophical cases are almost always meant to elicit a judgment1 or some other mental state about the situations they describe. The nature of the mental state elicited by philosophical cases is a matter of controversy, which will be the focus of the next sections. In this section, I will speak generally of “the attitude elicited by philosophical cases.” Philosophical cases do not specify whether the proposition expressed by the elicited attitude holds in the situation
1 In this book, I will usually use “judgment” and “belief” interchangeably. I take a judgment to be an occurrent belief.
described: They are neutral in this respect. The reader is meant to form an attitude about this proposition on the basis of her reading of the case.
Consider for instance the clock case (Russell, 1948, 170):
If you look at a clock which you believe to be going, but which has in fact stopped, and you happen to look at it at a moment when it is right, you will acquire a true belief as to the time of the day, but you cannot be correctly said to have knowledge.
This case, which suitably modified has often been used in contemporary epistemology, describes a hypothetical situation where the reader would form by luck a true belief about the time of the day on the basis of her visual experiences.2 The case is neutral with respect to the proposition of philosophical interest—namely, the proposition that the reader would not know the time of the day—and, following Russell, the reader is expected to form the attitude, on the basis of her reading of the case, that in this situation she would not know the time of the day.
What kind of mental state is the reader supposed to have about the situation described by a philosophical case? Is she supposed to imagine the situation described by, e.g., the clock case? To pretend that this situation holds? To suppose that it holds? Or something else (grasp it, understand it, etc.)? And, first, how do imagination, pretense, and supposition differ from one another? I will remain by and large non-committal about such questions since the argument developed in the next chapters does not depend on answering them. The minimalist characterization of the method of cases that I will endorse in this chapter only requires that, whatever attitude one has toward the situation described by a philosophical case, the reader can, first, reason about this situation, draw inferences about it, and categorize its elements, and, second, that she can reason, infer, and categorize using the very processes we use toward situations we believe to be actual. Imagination, pretense, and supposition plausibly meet these two requirements.3 In addition, because we could believe that the situation described by a philosophical case is actual and make a judgment about the proposition of philosophical interest on the basis of this belief, the attitude toward the situation described by a philosophical case (when it is not one of belief) should be as similar to belief as possible. Imagination, pretense, and supposition plausibly meet this third requirement.
Another issue I will remain non-committal about is the content of the attitudes elicited by philosophical cases. Philosophers have proposed many analyses of their content: According to some leading analyses, these attitudes express counterfactual conditionals, strict conditionals, or metaphysical possibilities.4 Nothing hangs on how this content is characterized, supposing it can be characterized uniformly across philosophical cases, and the remainder of this chapter examines the nature of the attitudes elicited by cases rather than their content.
2 It is sometimes said that similar cases are found in Indian epistemology, but that claim is controversial (for critical discussion, see Stoltz, 2007).
3 E.g., Nichols & Stich (2003); Weisberg (2014).
4 E.g., Williamson (2007); Malmgren (2011). For review, see Horvath (2015).
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MOTOR DISORDERS.
Paralysis (Akinesis) is loss of voluntary or involuntary muscular movement through defective innervation.
Paresis is a paralysis which is partial in degree; power of motion is impaired but not completely lost.
Hemiplegia is the loss of voluntary motion in many muscles on one side of the face or body. In general hemiplegia, the following muscles are usually excepted: muscles of the tongue, of mastication, of the eye, of respiration, of the neck and trunk, generally and of the proximal part of the limbs. The hind limbs are usually most affected, and muscles that are most exclusively under the control of the will those dominated by the cortical centres of the brain. When due to a clot on the brain or degeneration it occurs on the side opposite to that occupied by the clot, on account of the motor fibres crossing at the anterior pyramids of the medulla. Hemianæsthesia is a rare attendant and when present is often on the side opposite to the hemiplegia. Sensory fibres cross in the spinal cord, and the lesion is probably spinal.
Crossed Hemiplegia is motor paralysis of certain cephalic nerves (3d, 7th, 5th, 6th, and 8th,) on the same side with the clot or lesion, and of the muscles of the trunk on the other side. The cranial nerves proceed to muscles on the same side as their origin, while filaments going to the trunk through the spinal cord, cross in the pyramids (motor), or spinal cord (sensory). In crossed hemiplegia, hemianæsthesia is common with both forms of paralysis on one side.
Spinal Hemiplegia has the face and head sound (except sometimes the iris), and half the body paralyzed on the side opposite to that on which the spinal lesion (clot) exists. If anæsthesia exists it is on the side opposite to the lesion and posterior to it—the sensory filaments crossing just before leaving the cord.
Paraplegia is loss of voluntary power of one transverse half of the body; usually the posterior, and affects the tail, and has coincident anæsthesia, being due to a spinal lesion. Anal and vesical sphincters may or may not be paralyzed according as the lesions implicate their
respective spinal centres or not. If there is neither anæsthesia nor vesical paralysis the lesion may be cerebral, in the paracentral lobes of both hemispheres (meso-vertix at the fissure of Rolando).
Monoplegia is a circumscribed paralysis, as of one limb, or on one side of the face, one group of muscles or a single muscle. It may be due to cerebral, spinal or nervous lesion. Cerebral monoplegias are distinguished by: 1st, initial spasm; 2nd, absence of anæsthesia; 3d, persistence of nutrition; 4th, paralysis greatest in the distal portion of the member.
Localized Paralysis is usually due to lesion of a nerve, and is both motor and sensory. If due to a spinal lesion it usually affects one or more groups of muscles. In case the lesion is in the nerve, be guided, in investigating it, by Van der Kolk’s law, that the sensory fibres are usually distributed in the skin corresponding to the muscles which receive the motor fibres.
Pseudo-paralysis occurs from muscular disease, injury, inflammation or degeneration and has no appreciable central nor nervous lesion nor anæsthesia.
Spasm (Hyperkinesis); abnormal violent muscular contractions with or without loss of consciousness.
Tonic (tetanic) Spasm is violent and continuous.
Clonic Spasm is rapidly intermittent:—Contractions and relaxations.
Tremor (trembling) consists in small, intermittent, involuntary contractions.
Hemispasm affects the face, or limbs, or both, on one side of the body and may precede hemiplegia.
Monospasm affects one limb, one group of muscles or a single muscle. It may be due to lesion of the brain, of the spinal cord or of the nerves. Thus it may imply commencing disease of the motor centres or tracts.
Spasms of the Eyeballs (rolling of globe to one side), and Spasms of the Eyeballs and Head, are important indications of apoplexy. They imply disorder (commencing irritation) of the cerebral motor areas. Advanced disease would probably determine hebetude, coma, drowsiness, or palsy. If epileptiform it turns away
from the lesion. If hemiplegic it turns toward the lesion and away from the paralysis. If lesion of the pons it turns away from the lesion.
Paraplegic Spasm is a tonic spasm, partial in degree, causing stiff, tetanoid (spastic) walk. In all four extremities there may be mixed paresis and contraction. This often attends on hemorrhage into the meninges.
General Spasms, convulsions as in Eclampsia, Epilepsy, Chorea, Tetanus.
Local Spasms may be rhythmic or not, in slight cases to be seen only in the eyelids or superficial muscles as twitching, and occur in neurasthenia, or in poisoning by strychnia, brucia and other motor nerve poisons.
Incoördination (Dyskinesis) is the lack of the harmonious balanced movement of the various groups of muscles. Coördination of movement is due to a special mechanism in the spinal cord, and extending forward through the medulla oblongata, pons, and crura cerebri to the floor of the third ventricle. In the form of ataxia (lack of power of muscular control) it is usually the result of degeneration (sclerosis) of the superior columns of the cord, of the medulla, pons or crura. It may occur from degeneration or destructive change in the cerebellum, or from disease or section of the posterior roots of spinal nerves, or finally from the action of certain narcotic poisons (ptomaines, toxins).
Staggering (titubation) occurs from lesions of the cerebellum, medulla or pons; also from alcohol, opium, and other narcotics.
Reflex Action. The normal stimulation of different functions, motor, secretory, circulatory, etc., depends on the nerve centres in the spinal cord, which are roused into action by a centripetal impulse derived from a distant part. Thus the balanced contraction of the different muscles which preserves the equilibrium of the body, depends on the apprehension by the nerve centres, consciously or subconsciously, of such contractions (muscular sense), and it is largely under the control of the will. Here three impulses act coördinately: 1st, the afferent impulse from the muscle to the nerve centre; 2d, the efferent impulse from the nerve centre to the muscle; and 3d, the inhibitory or controlling, voluntary impulse from the sensorium to the nerve centre involved. In another case, savory
odors, sapid flavors and masticatory movements cause a free secretion from the salivary glands. Again, the scratching of a dog’s breast causes him to move his hind limb as if he were himself doing the scratching. Again, the pricking of a limb causes the prompt, even if involuntary, contraction of its muscles to withdraw it from the source of irritation.
Morbid Reflex. Reflex action may be modified in various ways as the result of disease or injury. It may become excessive from irritability of the organ from which the centripetal impulse starts, or of the reflex centre in the spinal cord, or of the muscle or other organ to which the centrifugal impulse is directed, or, finally, from impairment of, or separation from the inhibitory centre in the cerebrum. It may be impaired or abolished from degeneration or destruction of any of the tissues just named, or of the conducting nerves which connect them to each other.
The contraction and closure of the pupil under light is a reflex act from the retina on the optic lobes, etc., and from these through the motor oculi to the iris. This reflex is lost and the iris fails to contract in: anæsthesia of the retina; atrophy of the optic nerve; disease of the optic lobe; superior (posterior) spinal sclerosis; disease of the motor oculi; or disease of the iris.
The lumbar reflex is lost in many febrile states in the horse, so that pinching of the loins fails to produce wincing, and this becomes a test of the active persistence of the disorder.
Encreased Reflex is often noticed when the parts, including the spinal reflex centre, are disconnected from the brain: as in lesions or disease of the cord in front (cephalad) of its reflex centre. Here the cerebral or voluntary inhibition is lost.
Reflex Tonic Spasm of muscles around a diseased or dislocated joint, or of those controlling its action, often affords a valuable means of diagnosis, the possibility of nervous, muscular and tendinous disease being excluded.
TROPHIC SYMPTOMS AND DISORDERS.
Degenerative atrophy, in hæmoglobinuria, laryngeal hemiplegia, neurectomy, nerve lesion, brain or cord lesion, lead poisoning, disuse. Dermatitis, ulceration, morbid secretion, polyuria, mellituria, albuminuria, poisonous milk.
Degenerative Atrophy. From section, disease, atrophy or degeneration of nerves or nerve centres, the muscles, which they normally innervate, waste, often to an extreme degree. As examples of this we see the atrophy of the triceps extensor cruris and other groups in hæmoglobinuria, of the intrinsic laryngeal muscles in roaring, of the muscles supplied in neurectomy, and of groups of muscles in myelitis, broken back, lead paralysis, and scapular muscular atrophy. True to the law of wasting of physiologically inert organs, the nerves are atrophied and degenerated, and often also the bones, joints and skin.
The degeneration of an active organ applies to the nervous tissues themselves. According to the law of Waller, the nerve fibre (axis cylinder), when cut off from its nutritive centre (cell body with nucleus) degenerates and ultimately perishes. The axis cylinder is a component part of the neuron, which includes also its continuation in the cell and nucleus, and when the latter, which is the source and origin of both nerve impulse and trophic control, is lost, the inactive axis of the nerve fibre degenerates. This law is now availed of in tracing the distribution of nerve filaments, the degeneration being found in those that have been cut off from their nerve cells while those that come into the nerve trunk from other sources, distal of the injury, maintain their integrity.
In addition to this peripheral atrophy, a degeneration central of the injury to the nerve is seen under certain conditions, but especially in intrauterine life. In such cases the atrophy may extend
up to and include the central nerve cells, causing a secondary central nervous lesion from an initial peripheral one.
By bearing these laws of nerve atrophy in mind, lesions that would otherwise be obscure, may be satisfactorily accounted for.
Eruptions and Ulcerations of Nervous Origin. Herpes or shingles in man is now recognized as a nervous disease, circumscribed to the distribution of given nerves and occurring unilaterally or bilaterally. Deep-seated dermatitis, vesicles, neuralgia, pain, itching and formication are common accompaniments. The whole is traced to disease of the ganglion on the posterior (superior) root of the spinal nerve distributed to the part. This establishes a principle, and in inscrutable and obstinate, circumscribed skin disease the veterinarian should see if it coincides with the distribution of one or more sensory spinal nerves.
Ulcerations are often caused by the lack of protection of a part after paralysis, thus perforation of the cornea will follow section or disease of the trigeminus. These may be prevented by carefully covering the part, and even cured by a fine protective covering like collodion.
Alteration of the Secretions often follow on section of the sympathetic trunks, that of the cervical sympathetic in rabbits causing excessive congestion of the facial skin, with exudation and scabby product, also profuse secretion of sweat, tears, and ear cerumen and dry, scaly skin.
Polyuria is determined by section of one point of the medulla behind the root of the vagus, mellituria by puncture between the vagus and auditory nerves (the hepatic vaso-motor centre), and albuminuria by a puncture in front of the latter. Impairment of the hepatic vaso-motor tracts in the spinal cord, or of the anterior or posterior cervical sympathetic ganglia, or of the first thoracic ganglion equally determines nervous mellituria.
Poisonous milk produced in hard worked mares, or over-excited dams of other species, causing dyspepsia, diarrhœa, arthritis or other trouble in the suckling, must be in part attributed to nervous disorder.
Practically all secretions and nutrition are largely under nervous control, so that modifications in quantity or quality can often be
These are necessarily much less obvious to the veterinarian than to the physician of man. Yet in certain cases they may be observed directly, and in others deduced from dependent symptoms.
Hyperæsthesia is a state of exalted excitability of any part of the sensory nervous apparatus.
Cutaneous hyperæsthesia is that condition in which the slightest touch gives rise to an instant and extreme response. Some nervously organized mares which are dangerously ticklish and irritable, afford physiological examples. The surface soreness and sensitiveness which exist in the febrile chill, in wounds, dermatitis and neuralgia give pathological examples. It is further seen in certain cases of meningitis (cerebral and spinal), spinal irritations, rabies, tetanus and neuritis.
Hyperæsthesia to cold is seen in neuralgia, rheumatism, the early stages of many fevers (chill), in myelitis, neuritis, nerve injuries, and in posterior (superior) spinal sclerosis.
Hyperæsthesia of the muscles may be noted in tetanus, muscular rheumatism and neuralgia.
Visceral hyperæsthesia is shown in many cases of spasms of involuntary muscles (colic, arrest of intestinal calculi, gall stones or urinary concretions), and in inflammation of serous membranes (pleurisy, peritonitis).
Paræsthesia. This is a painful or morbid sensation caused by a lesion in the central nervous structures or in the nerves, but referred by the sufferer to some peripheral organ over which such centre
presides. It may even be referred to an organ or part that has been amputated or otherwise removed. This may cause lameness of a kind to indicate suffering in a given muscle, tendon or joint, when the cause is purely central. In dourine, sexual acts are excited which have their real source in the nerve centres. The rabid dog snaps at imaginary flies in mid-winter, when such insects are only phantoms of his brain.
Pressure on a nerve trunk induces sensations of tingling, vibration, formication, heat, cold, and paresis, referred by the mind to the part to which that nerve is distributed, and when the pressure is removed these sensations recede in the order in which they came. This may explain some occult cases of lameness.
Itching may be a pure, persistent neurosis without any skin lesion. Treatment should then be addressed to the nervous system.
Anæsthesia, or absence of sensation, is in its degree partial or complete. The latter is familiar as occurring in parts the sensory nerves of which have been cut across, also in parts the sensory nerve or nerve centres of which have become completely degenerated. There is no response to the prick of a needle, the touch of a hot wire, to pinching or cutting. If the nerve remains intact as far as the spinal centres, reflex action may still occur, but the patient himself has no consciousness of this nor of the injury causing it. Accordingly, he makes no movement of head, ears, eyes, or other parts still dominated by the brain.
In partial or imperfect anæsthesia the response to irritation is less marked and may be even delayed. In some forms of central lesions the response to a prick may be delayed two, five, or ten seconds, or even more.
Anæsthesia causes awkwardness or uncertainty of movement, especially if the subject is blindfolded.
Anæsthesia may be induced by medicine, as in the general anæsthesia of etherisation, or the local anæsthesia caused by the topical application of cocaine or carbolic acid.
Analgesia, or insensibility to pain, may be present in cases in which ordinary sensations are still felt. It may be caused by cocaine, alcohol, and to some extent by carbolic acid.
Hyperalgesia is the opposite of this condition, and may be seen in certain irritable conditions of the nerve centres.
PSYCHIC SYMPTOMS AND DISORDERS.
Limitation in lower animals. Effects of age training, race heredity, individual and racial peculiarities, exhaustion, prostration, dementia, cerebral congestion, compression, degeneration, narcotics, ptomaines, toxins. Controlling absorption in another trouble. Delusions, hallucinations, vice, violence, œstrum, fatigue. Cerebral source of motions.
These have a much more restricted field in the lower animals than in man in keeping with the limitation of the mental faculties, and they may often be traced to demonstrated structural disorder. Yet some emotions of joy, fear or rage run very high and are comparatively unchecked by high mental development or mental training. The effect of training is, however, very marked in the more educated animals.
Age modifies by the sobering that comes from experience and habit. The frolics of puppies, kittens, lambs, foals and calves are in marked contrast with the sedateness and stolidity of old dogs, cats, sheep or cattle.
Training is seen in the educated horse which would have been panic stricken at sight of a locomotive, flag or floating paper, at the smell of a lion or bear, at the sound of a gun or drum, and which will now boldly face any one of these with no manifest tremor. The emotional puppy can be trained to soberly fetch and carry, to drive sheep or cattle without biting, to lie sentinel by his master’s property, to point at birds without seeking to catch them, or to carry shot birds without devouring them.
Race heredity comes from the training along the same lines in many successive generations. Thus the more domesticated breeds of dogs (shepherd, poodle, and greyhound) are very affectionate; other breeds (bull, mastiff, bloodhound) are lacking in this character. All
trained races take naturally to the occupations of their ancestors. Some (horses, cattle and sheep) are easily panic-stricken, (stampeded). Some (turkeys, roosters) are not easily stampeded. Some (skunks), having effective sources, of defence, have little fear of man.
Individual and racial mental dullness and torpor must also be recognized. Some are stupid and slow, others alert and quickly responsive. Some horses are not level-headed and become uncontrollable in difficult situations. Some dogs are so emotional as to endanger their lives from sudden heart trouble. Some horses, dogs and cats will pine and die when separated from their fellows or human friends. Extreme timidity, or sudden rage may be so marked as to constitute a virtual morbid phenomenon. Sluggish cerebral and mental action may result from exhaustion, prostration, or dementia; also from cerebral congestion, pressure and degeneration; or from poisoning by narcotics, ptomaines or toxins (opium, hyoscyamus, Indian hemp, dourine, milk sickness, etc.). It may come from profound absorption in another object, as when the rabid dog bears whipping without a howl.
Delusions or hallucinations are shown in the rabid dog snapping at flies, or attacking his friend or master as an enemy, as well as in other forms of delirium. Narcotics, such as opium, Indian hemp, etc., ptomaines, toxins, and (in dogs) essential oils cause delirium by acting on the nerve centres.
Vice in its various forms may become a genuine neurosis, the animal losing control of its actions.
Violence in the form of self-defence or aggression is seen in mares in heat, in bulls or stallions under sexual excitement, in animals roused by inconsiderate whipping, or in bulls looking on scarlet clothing.
Some high-spirited animals, under extreme fatigue from overwork, sometimes become violent but resume their docility under rest and food.
In all cases we must know the normal of an individual animal to enable us to properly appreciate any apparent deviation from the psychic norm. No less essential is it to take into account the environment and treatment of the patient.
With regard to localization of cerebral lesions, Sequin thinks emotions are probably generated in the basal ganglia such as those of the pons and thalami, while inhibition depends on the anterior cerebral cortical convolutions.
DIAGNOSIS, SYMPTOMS AND THEIR IMMEDIATE CAUSES. LOCALIZATION OF LESION IN SPECIAL SYMPTOMS.
Spasm, pain, numbness irritation. Paresis, paralysis, anæsthesia (constant) destructive lesions. Both combined variable symptoms, recurrent. Definite, fixed symptoms structural lesions, usually progressive. Symptoms, variable as to place, time, subsidence and recurrence functional lesions. Brain lesions. Pressure on brain pain, spasm, nausea, dullness, blindness, stupor, coma, palsy. Congestion and anæmia synchronous. Lesions of cortex. Encephalic lesions hemiplegia, with spasms, increased reflexes, spasms follow cranial nerves, vertigo, apoplexy, epilepsy, dementia, coma, little muscular atrophy, or dermal sloughing. Spinal lesions, paraplegia without spasm, reflex reduced or nil, follow spinal nerves, head symptoms less, much muscular atrophy, bed sores. Sensory and motor tracts, in crus cerebri, respiratory centres inspiratory expiratory, inhibition. Salivation, sneezing, coughing, sucking, chewing, swallowing, vomiting. Cardiac centres, accelerating and inhibitory. Vaso-motor centre. Spasm centre. Perspiratory centre. Pons. Corpora quadrigemini, crura cerebri. Thalamus, corpus striatum. Cerebellum. Cerebral cortex: in ass; in dog. Spinal lesions: lateral half section: central anteroposterior, vertical section: superior columns: inferior columns: cervical lateral columns: respiratory tract: glycogenic centre: pupillary dilator: cardiac accelerator; vaso-motor, sudoriparous: centre for anal sphincter: for vesical sphincter: genital centre: vaso-motor and trophic centres: muscular sense tract: superior column and Goll’s. Table of phenomena from cord lesions.
In Irritation of nervous organs the symptoms (spasm, pain, numbness) are usually intermittent.
In Destructive Lesions of nervous organs the symptoms (paresis, paralysis, anæsthesia) are usually constant. When irritation and destruction are associated the symptoms are variable and frequent. The characteristic symptoms of the two may coexist or succeed each other.
Structural Nervous Lesions have symptoms that are definite in their area of distribution, nature (spasm, paralysis) and permanency. Objective Symptoms predominate and the case is likely to be progressive and fatal.
Functional Nervous Diseases have symptoms of indefinite distribution, variable in character, with intermissions and spontaneous disappearances (as under marked excitement) and subjective symptoms predominate. They may, however, last for a length of time without change.
Localisation of Brain Lesions.
Lesions of the cranial nerves and their superficial and deep centres of origin need not here occupy attention. These may be studied in works on anatomy and physiology. Attention may be drawn rather to the remoter effects of ganglia which affect or control distant action, and to general pressure on the encephalon.
General Pressure on the Encephalon, whether through fracture of the cranium and depression of bone, by acute congestion, by blood extravasation, by inflammatory exudation, or by acute abscess, will cause pain, spasms, nausea, dullness, blindness, stupor and coma. After expulsion of the cerebro-spinal fluid from the cranial cavity, the increasing pressure compresses the blood vessels, reduces or interrupts the circulation and abolishes the functions in the parts deprived of blood. Thus congestion of one portion of the encephalon is usually associated with diminished circulation in another portion. Disorder in the first may occur from hyperæmia and irritation and in another part from a consequent anæmia.
Destructive Lesions of Cortex of One Cerebral
Hemisphere may or may not cause permanent symptoms, as shown by the passage of a crowbar through the front of the left hemisphere, yet the man survived for 13 years and showed no loss of intelligence, his disposition and character alone having changed for the worse. The one hemisphere may by itself sufficiently control mental acts, while the other lies dormant or may even have undergone degeneration.
Diagnosis of Encephalic and Spinal Lesions. The following may be taken as guiding principles:
Encephalic: Hemiplegic or bilaterally hemiplegic grouping of symptoms.
Spinal: Paraplegic grouping of symptoms.
Encephalic: Frequent contracture or spasms of paretic muscles.
Spinal: Paralysis more perfect and continuous.
Encephalic: Reflexes in affected muscles increased: Cerebral inhibition absent.
Spinal: Reflex abolished or reduced in parts the seat of the lesion.
Encephalic: Spasms in areas of distribution of cranial nerves (not spinal.)
Spinal: Spasms and paralysis follow distribution of spinal nerves.
Encephalic: Head symptoms frequent (vertigo, apoplexy, epilepsy, dementia, coma).
Spinal: Relative absence of head symptoms.
Encephalic: Comparative absence of marked muscle atrophy.
Spinal: Atrophy in special muscular groups.
Encephalic: Little tendency to form bed sores.
Spinal: Tendency to form sloughs and bed sores.
Sensory (Æsthesodic) and Motor (Kinesodic) Tracts in Encephalon.
In the crus and above, the sensory tract lies dorso-laterad of the motor tract, forming about one-fifth of the crus, and extending upward through a white layer bending inward to form an angle and finally diverging to the different cortical convolutions. The motor tract is mainly contained in the inferior pyramids of the bulb, and constitutes the median two fifths and basal two fifths of the crus. Without entering farther into this subject it will be observed that lesions of the outer layer of the crus and its radiating fibres may cause hemianæsthesia of body or head, including the eye, while lesions of the median and basal layers and radiating fibres induce hemiplegia of the head, tongue, fore limb, hind limb, trunk, etc.
Respiratory Centres, Inspiratory and Expiratory are in the floor of the fourth ventricle between the centres for the vagus and accessory nerves, and are directly stimulated by the CO2 in the blood. Secondary subsidiary centres are in the optic thalamus, in the corpora quadrigemini both anterior and posterior pairs, and finally in the cervical spinal cord, so that disorder of respiration may occur from lesions in these points as well as in the main oblongata centre.
Respiratory Inhibition and arrest depend on the vagus, the superior and inferior laryngeal nerves.
The Salivation Centre also lies in the floor of the fourth ventricle and stimulation of the medulla causes free secretion.
The Centres for Sneezing, Coughing, Sucking, Chewing, Swallowing and Vomiting are also seated in the oblongata, so that any one of these phenomena may come from a central irritation. In bulbar paralysis the loss of power usually extends from the tongue through the lips, cheeks, jaws, pharynx, larynx, to the respiratory muscles and heart. Coughing may be roused by irritation of the external auditory meatus, liver, stomach, bowels, or generative organs as well as from the air passages.
Cardiac Accelerating and Inhibiting Centres are both present in the bulb, the latter receiving its afferent impulse mainly through the vagus nerve. Stimulation of the vagi, anæmia of the bulb through decapitation or through tying both carotids, hyperæmia through tying of the jugulars, a venous state of the blood, and blows on the abdomen all slow or arrest the heart action. Digitalis or muscarin has a similar effect. The heart action is accelerated by febrile and inflammatory affections, by a high or low temperature by section of the vagi, by sipping of cold water, by atropine or curari, and by salts of soda. Potash salts on the other hand restore the inhibitory action of the vagi and lower the heart’s action.
The Vaso-Motor Center is also in the oblongata and the contraction of the vessels with increase of arterial pressure may ensue from afferent currents in the sympathetic nerve and many sensory trunks. The varying activity is seen in blushing, in the congestion of mucous membranes under rage or excitement, in the capillary contraction in the early stage of inflammation, in the second stage of capillary dilation, in angioma or nævus and in extensive congestions and hæmorrhages in different organs. The arrest of bleeding under fainting is due largely to the anæmia of this centre.
A Spasm Centre the pricking of which causes general convulsions lies in the medulla oblongata at its junction with the pons. This is excited by excess of carbon dioxide in the blood, by suffocation, drowning, by anæmia of the bulb from bleeding or ligature of the carotids, by venous congestion after ligature of the jugulars, or by the direct application to the part of ammonia carbonate, or salts of potash or soda. It may also be roused by afferent nervous currents from different peripheral parts (spinal cord, sciatic nerve, etc.).
A Perspiratory Centre is found in the medulla, on each side, which may be roused into action by diaphoretics (opium, ipecacuan, tartar emetic, Calabar bean, nicotin, picrotoxin, camphor, pilocarpin, ammonia acetate, etc.).
The Pons like the medulla is at once a ganglionic and conducting organ, and its lesions may lead to arrest of nerve currents generated above or below it, or to the failure to develop currents in its own centres. Stimulation of its superficial layers may be without effect,
but if this is carried into the centre epileptiform convulsions ensue. Lesions of one side of its posterior half cause facial paralysis on the same side and motor and sensory paralysis on the opposite side of the body (crossed hemiplegia). Lesions of one side of its anterior half cause paralysis in both face and body on the same side. This depends on the crossing of the fibres midway back in the pons, which cross again in the medulla (motor fibres) and in the spinal cord (sensory fibres). Lesions of the pons are liable to interfere with the functions of the trigemini, the oculo motor and the superior oblique, and to determine epileptic movements and loss of coördination of sensoriomotor movements. Lesions of the superficial transverse fibres (median cerebellar peduncles) tend to cause involuntary movements to one side.
Lesions of the Corpora Quadrigemina cause disturbance of vision, failure of the pupil to contract to light, blindness, paralysis of the oculo-motor nerves, and lack of coördination of movements. Stimulation of one anterior corpus causes rolling of both eyes to the opposite side, with, if continued, a similar movement of the head and even of the body (horse in mill, or index motion, or rolling on its axis).
The Crura Cerebri are conducting bodies but contain also different nerve centres. Lesions of one crus cause violent pain and spasm on the opposite side of the body, followed by paralysis. The oculo motor may be paralyzed on the same side, but the face and tongue on the opposite side, owing to the fibres crossing in the pons. There may be turning movements.
The Optic Thalamus transmits sensory currents to the cerebral cortex. Lesions in this organ cause sensory paralysis on the opposite side of the body. Afferent currents that do not traverse the thalamus cause reflexes only. It contains one of the roots of the optic nerve and its destruction will impair vision. Its injuries may also produce turning movements.
The Corpus Striatum transmits motor currents originating in the cerebral cortex. Lesions of its interior (lenticular nucleus) cause motor paralysis and sometimes anæsthesia on the opposite side of the body. Electrical stimulation of this nucleus causes general muscular contractions of the opposite side of the body. Irritation of the surface layers is painless and symptomless.
