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CERTAINTY.

An epistemic property of subjects and beliefs.


Kinds of Certainty. Psychological Certainty. Epistemic Certainty. Moral Certainty.

Although all three kinds of certainty are philosophically interesting, it is epistemic certainty that has traditionally been of central importance.


Indubitability. Certainty, whether applied to what is undoubted or to what is indubitable is subjective. Cogito: I am thinking therefore I am. Decartes is thinking. Decartes exists. (i) I can know that my clear and distinct perceptions are true only if I first know that a non-deceiving God exists, and (ii) I can know that a non-deceiving God exists only if I first know that my clear and distinct perceptions are true.


Common Sense Realism. There is a world of physical objects Which continue to exist whether or not we are perceiving them. These objects are more or less as they appear to us because our eyes, ears, tongue, skin and nose are generally reliable They give us a realistic appreciation of what is actually out there. It is possible to go through life without questioning the assumptions about sense perception.


Scepticism and Fallibilism. Scepticism is the view that we can never know anything for certain, that there is always some ground to doubt even our most fundamental beliefs about the world. Incorrigible: Conclusively verified Not subject to further tests. Fallibilism is a modified scepticism which maintains that no belief is finally and conclusively justified, that no belief is incorrigible.


Dreaming? How can I be certain that instead of standing here talking about certainty, I am not lying asleep somewhere in Italy dreaming that I am awake here in Belfast talking to you about certainty? Cannot always be dreaming. Dreams are different. Can’t ask: ‘Am I dreaming?’


Memory and Logic. Sceptics rarely call into doubt the reliability of Memory and Logic. Not consistent.

Human memory is unreliable. Past Perceptions = the self.


Representative Realism. Representative Realism is a modification of Common Sense Realism suggesting that all perception is a result of awareness of inner representations of the external world. What happens when one sees a butterfly? 1. Homunculi in the Head. 2. Makes the Real World Unknowable.


Idealism. Idealism argues that there is no justification for saying that the external world exists at all, since it is unknowable. Objects only exist as long as they are being perceived. Provided that no one else is perceiving them at the time. Leads to Solipsism.


Causal Realism.

Causal Realism assumes that the causes of our sense experience are physical objects in the external world. The main biological function of our senses is to help us find our way around our external environment. Causal realism is the most satisfactory theory of perception to date, and it makes the assumption that there is a real world out there. Most of us are committed to the certainty that a real world exists independently of us.


Certainty