Irish Research Council Postdoctoral Research Project 2010-2012; for details on the Irish Research Council, see http://www.research.ie; for details on awardees that year, see http://www.research.ie/awrads/scheme-2)
Should we hold that there are illusory experiences of time? We ought not if possible; doing so causes problems in trusting our experience generally. However, to deny alleged evidence of temporal illusions may commit us to certain counter-intuitive conceptions of time.
Scientific theories as well as legal judgments and social policy decisions depend on empirical data, and empirical data depend on our experience of the world. Yet, there is an ancient question about such dependency: can we trust our data? The existence of perceptual illusions demonstrates that we cannot always do so: how the world appears to us is not always the way it is. Yet, if we assume that anything we experience may be illusory in this way, it seems that we lose a significant constraint on scientific theory. This proposal considers the possibility of protecting at least one important feature of what we experience from being illusory – the experience of time.
Can we ever trust our senses about anything we experience? If we never can, it seems as if any claims from empirical evidence lose force. Just because there seems to be X does not mean that there is X; so a theory that denies or does not account for X need not be moved by its appearance; the appearance of X may, after all, just be illusory.
However, this runs counter to the scientific method according to which scientific theories are supposed to be constrained by empirical data. However, if we assume that appearances may always be illusory, then we no longer have such constraint. This is a problem for the natural as well as for the social sciences and other contexts in which judgments and decisions are based on experiential evidence and, for example, witness testimony ( such as history and law).
Yet, what are we to do? The evidence is overwhelming that there are perceptual illusions. One question we might ask is, given we need appearances as a source of knowledge, can there be anything which we can take to never be an illusion? Is there any appearance of which we can say with certainty that it cannot be illusory?
I argue that we can and should deny illusory status for at least some apparent features of time. That is, whatever else we may hold to be illusory, we need not and ought not accept illusions of time – what I call temporal illusions. However, I think that we can only deny that there are temporal illusions if we also accept certain conceptions of time, a facet of the discussion so far neglected in the literature.
The Importance of Temporal Illusions
But why does it matter in particular whether one denies the possibility of temporal illusions?
I will argue that it matters because time is fundamental to our experience in general (something originally made explicit by the Enlightenment philosopher Kant). Whether we hear music, have a thought, hold an apple in our hand, taste it, or watch a plane taking off, all such experiences are of things persisting or undergoing change. Both of these are experiences of time. Thus, if such experiences of time could be illusory, the experience of music, thought, apples, or planes can also. I argue, then, that the possibility of temporal illusion undermines any experiences as constraints on theory.
Yet, there does seem to be a great deal of supporting evidence for temporal illusions. Some of it is uncontroversial (although I still intend to examine it), e.g., how long ago something feels seems readily exposed as false even by the subject recalling the duration; the surprise of learning that I read a book many years earlier than it ‘feels’ I did is common. But others are more problematic: some kinds of temporal illusion concern what we perceive.
- The Waterfall Illusion : after focusing observation on constant flow, e.g., waterfalls, the immediate observation of stationary objects seems to be of the objects moving, e.g., boulders near waterfalls seem to shift and slide. The suggestion, then, is that we are seeing motion where there is no motion.
- The Phi phenomenon: a quick succession of spatially separated flashes gives the appearance of a single light in motion; the apparent temporal order of the stages of the motion either (i) requires commitment to a variety of controversial views, e.g., that we perceive the future, or (ii) we perceive only an illusion of temporal order.
I will argue that, although there are illusions here, they need not be ones of time. Instead, they can be illusions of something else, e.g., for ‘illusory’ motion, of WHAT is moving; for alleged illusory order, of WHAT is ordered.
Illusions and The Conceptions of Time
I suspect the answer may depend on our conception of time. Different conceptions of time make different claims about what exists. For example, the (prima facie) intuitive presentist conception of time holds that only the strictly present moment exists while the (prima facie) counter-intuitive eternalist conception of time holds that anything at any time exists. Presentism is generally thought to be the intuitive view. However, in the last century, developments in physics, i.e., Einstein’s relativity theory, has led to a majority of theorists of time to reject it, and so to endorse some variant of eternalism.
I will argue that the dependency of what we hold to exist on our concept of time makes whether or not we hold something to be illusory also dependent on our concept of time. This may include whether or not alleged ‘temporal illusions’ are illusions.
However, it may be that we must still accept temporal illusions regardless of our conceptions of time. So the final questions of this project are: what other reasons do we have to think something is an illusion? And how do they apply to the illusions in question?
These questions involve engaging with the general literature on illusion, both contemporary and historical. This is to establish some general rules about the nature of illusion (or, alternatively, to find that there are none). In doing this, the project takes on another dimension, as a general discussion on illusion. Thus, whatever the status of temporal illusions or how they may be dissolved, this project also produces a resource for those interested in illusion generally.