ian phillips
perceiving the passing of time
draft paper
‘presently’ perceived stimuli, and there is scope (how much being an empirical question) for comparison over slightly longer periods, or relative to some abstracted standard (e.g., the average length of recent stimuli). The crucial point is that we do not strictly perceive events as having any metric duration. Such a view of duration perception would fit with a more general view of the perception of extensive magnitudes as wholly relational. For example, according to such a view of size perception, we never simply perceive the length of a stick, but rather only its length relative to the length of other objects. Again, in the simplest cases, both objects of the comparison will be objects within the present visual field, but there is scope to allow for comparisons with temporally adjacent, and ‘abstracted’ objects. A purely relational view of perceived magnitudes has consequences for hypothetical extreme cases. Thus, Shepard: Imagine a line segment that, although it does have a definite physical length (…), is somehow presented in such a way as to prevent comparison of its visual extent with any reference extent (…). Although the line could presumably still appear to be extended under such hypothetical conditions, it is doubtful whether its extent could be appreciated as a uniquely defined psychological magnitude … natural selection has favoured nervous systems that are primarily attuned to what is “out there” in the external world; and … what is out there is most easily and accurately determined by making comparisons. (1978: 463)
In the temporal case, the analogue of Shepard’s line would be a brief event with some definite objective duration somehow presented so as to prevent comparison of its duration with any reference duration. In this situation it is tempting to conclude that although the event would still appear to have what Ward (following Kant 1781/2003: A805/B833) called ‘protensity’ (1918: 119), it could not be appreciated as having any duration proper. For that comparison is needed. However, whether or not we agree with Shepherd’s view of the spatial case, it is doubtful that we can in fact imagine an analogous temporal case. The reason for this is that whilst it might be possible to eliminate all comparative temporal magnitudes in the subject’s apparent perceptual environment, the elimination of all temporal comparisons
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