It’s all in your mind, man.
The philosopher in me is used to hearing this, usually expressed with either concern for my well-being or a desire for me to leave the room. My response, typically, is to utter “exactly!” as the door closes behind me. Most people accept that at least some things are just in the mind: subjective sensations such as feelings of warmth and coolness, or how things taste, and even colors. But in fact, I think, it is all in the mind.
Consider a typical dream. You’re on an island, say, in the Caribbean, the sun is shining, the ocean is a gorgeous blue, you’re sipping a cool pina colada, under a coconut tree, with (literally) the man or woman of your dreams, or maybe both … And then you wake up. And you’re in your bed, at night, in winter, in New Jersey, with no sunshine, no ocean, no pina colada, and desperately, desperately alone. We’re all familiar with this phenomenon: how things appear in the dream is just not how things really are. But we’re less familiar with the implications.
In the dream, at one moment, you gazed at the coconut tree. But what, exactly, were you seeing there?
It was not a real -- that is, physical -- tree, because there is no physical coconut tree in your lonely New Jersey room. Indeed it could not have been a physical tree because, while dreaming, your eyes were closed: you weren’t physically seeing anything at all. You must have been seeing something else: a mental image of a tree, a mental tree. The same goes for everything else in a dream. What we see in dreams are mental images.
Could we say, perhaps, that your dream was of some physical tree you have seen, which your memory is now recalling? After all, even if a dream is essentially fictional it is based in reality: you have seen trees, and oceans, and islands, and your mind and memory are capable of storing and reordering all the components in new ways.
That may be true -- but still. When you “store” a memory, so to speak, just what are you storing? The real physical tree? But how can any physical object literally be “stored” in a mind? Whatever goes on in your mind must ultimately be grounded in your brain. But the real physical tree surely is not literally stored anywhere in your brain. Similarly, when your mind calls up a memory, just what is it calling up exactly? Again, the real physical tree? But that tree is far far away; it may even by now be long out of existence. It makes more sense to say this: what gets stored in memory, and “recalled,” is not the physical object itself, but some mental image of it. Mental images can be stored in minds, and can exist long after the physical object of which they’re an image is gone.
Now you are awake. If you are lucky, you’re reading this book right now on an island, in the Caribbean, the sun is shining, the ocean is blue, you’re sipping a cool pina colada, under a coconut tree, with the men and women of your dreams … Look at the tree. Your visual experience is in every way exactly like your dreamed visual experience of that tree. But in a dream, what you see are only mental images of objects. So what you see, when, while awake, you look at a tree -- is not a real physical tree.
It is all in your mind, man.