Previous: Conditions of Illusion II
Ought we hold the following as a principle about experience?
For any entity or property x that can be apparent, in cases where there is no x, our perceptual (and, more broadly, experiential) capacities include the ability to generate appearances of x.
Here is either the same idea put in a different way or an ever-so-slightly different idea:
Due to how actual experience is constituted, it is possible that, for any appearance of x, x’s appearance can occur without x. How actual experience is constituted includes the capacity, for any apparent x, that there is an illusion of x.
Here is one more way of putting it.
For every case where appearances and reality match, then given our experiential capacities, it is possible for there to be a counterpart case where appearances and reality do not match.
(I think it is plausible that) It follows from holding this (or any of these, if they are different) as a principle that, for every veridical experience, every case where how things appear is how things are, there can be a counterpart non-veridical experience where how things appearis not how things are.
Expressed in the last way, I call this the Principle of Universal Illusory Counterparts.
Seeking an answer to the sceptics’ challenge to the dogmatists, Descartes decides to put aside all beliefs about which he had reason to doubt. In Meditation 1, he begins with beliefs derived from the senses:
“All that I have, up to this moment, accepted as possessed of the highest truth and certainty, I received either from or through the senses. I observed, however, that these sometimes misled us; and it is the part of prudence not to place absolute confidence in that by which we have even once been deceived.”
Descartes then moves on to the possibility that everything, no matter how certain it seems, is not how things are. This includes the certainty that one is awake: he allows the possibility that, even as one is certain one is awake, it is the case that one is dreaming.
Let us assume that this is possible: your whole life is, and has been, a dream. Everything that you seem to remember, and everything you seem to see, hear, and otherwise perceive, is not how things are. Or, perhaps, let’s not even go this far. Let’s just go back to your teenage years (if you’re an adult) or childhood (if you’re a teenager): some night, you went to sleep and dreamed everything that appears to have happened to you since then. You are still in that night, dreaming, much younger than it seems to you that you are. At some point in the future, maybe before the end of this sentence, maybe much further in this dreamed life, you will wake up. This life you believe you have lived has no existence. All the people around you are fictions. When you wake up, it will stay with you as any dream does, perhaps make you feel — briefly– sad, amazed, uncertain, relieved, but like all dreams it will fade. Like most dreams I’ve ever had, you’ll forget the details soon enough and simply say ‘I had such a strange dream. I was so much older than I am now, and this happened — and this — and this’, but then you will get on with your — so it seems to you — real waking life.
If the above is possible, then this is also possible: The vivacious, rich, detailed experience in perception (and remembering) is entirely mistaken. It seems to be of a rich, mind-independent world, full of spatial and temporal entities possessing mind-independent and even body-independent properties such as shape, timbre, colour, weight; but this experience is not of those entities and properties. Even if there are such entities and properties, you have no experience of them. What seems to you to be perceptions or memories are not connected in the ‘right way’ to them (e.g., through causal chains, Coates 2000).
I do not want to dispute this possibility. To put it in terms of possible worlds, I will assume like many that: there is a possible world which seems exactly the same as the actual one but which is completely different to the actual world on the macroscopic and otherwise observable scale.(Although Bouiswama 1949 has an interesting way of resisting this idea.)
However, I do want to dispute that there is a need to accommodate such a world in our explanations of our own perception and experience — that is, of the perceptual and experiential systems that we ourselves, actual beings in this world, possess.
1. This is not to say that, for any particular x, this ever happens to either ourselves or any other actual individual being that has experience. It is only to say that it is possible, given any such actual beings’ capacities. The range of possible ways actual experience can occur, given how it actually works, includes a separation of appearance and reality for any x (which is I suppose another way of putting this).
2. Putnam discusses the relevances of differences on the microscopic scale to psychological states, in terms of their reference/content/meaning, and truth-value. Perhaps one could also run something similar on the cosmological scale, so that if a subject ended up, unknown to themselves, passing through a multiversal wormhole into a universe in which the galaxies are not drifting apart, or where the sun is the centre of the universe, they would mean a different thing when they talk about the sun thinking, or the milky way galaxy glowing beautifully at night. But, in any case, I don’t think that water happening to be H2O or the universe being properly described according to a sort of neo-Ptolemaic system would make our experience of the world mistaken or illusory in the sense intended here.