June 7, 2012 11:46:57 AM
If you are a Firesign Theater fan, you will remember Principal Poop's pep rally speech in the mock radio play "Porgy and Mudhead in High School Madness." A heckler in the stands keeps yelling at the principal, and one of the less obscene things he yells is, "What is reality?" Well, that would seem an easy question, but Poop does not risk a reply. Smart fellow. Like lots of seemingly easy questions, it's surprisingly complicated. In _Reality: A Very Short Introduction_ (Oxford University Press), philosopher Jan Westerhoff intends to show that we all assume reality is pretty simple, and we are all foolish to make the assumption. Well, maybe not; if you think that you are you, and that you are now reading this sentence, and you are not fretting that you are just someone in a dream, this, Westerhoff says, "reflects a healthy psychological attitude." But if you have never thought about how you can tell in a dream that you are dreaming, or whether the letters you now see in front of you are really there, or if they are the product of someone else's brain, or if the present is the same for everybody, then he says this "suggests a lack of philosophical imagination." Westerhoff's funny and sometimes alarming book is indeed very short; as part of Oxford's admirable "Very Short Introduction" series, it has to be. There are 123 pages, including nine pages of handy references for anyone who wants to dig deeper, and find out how unreal reality really is.
Of course, to answer "What is Reality?" requires definition, and like most definition problems, there are different definitions and the answer to the question depends on which definition you want to use. Westerhoff has taken five different potential definitions, well known to philosophers, given them snappy names, and applies them to see what happens. The Matrix Definition is the one I think we most often go by; what is real is what is out there according to your senses. The 1984 Definition is that reality is not "out there," and not even in the individual mind, but is that which appears to be real to the senses of a sufficiently large number of people. Johnson's Definition is that reality is the stuff out there that is not made up and doesn't go away when one stops believing in it. The Apocalyptic Definition is more restrictive, in that it allows in only things that would be there if there were no human minds to consider or operate upon them. The Turtle Definition regards as real only the rock-bottom level of objects, below molecules, atoms, nuclei, quarks, strings, and whatever other level we can come to. Each definition is useful, and, distressingly, none of them applies in all cases and they argue among themselves.
The easiest reality conundrum to contemplate is that of dreaming; dreaming certainly seems real at the time. If you are dreaming right now, in your dream you are reading these words and thinking about them, and if you have a coffee nearby, you are sipping it and enjoying the taste. If it is a dream, who cares? You are getting all the experiences. And yet, if you are dreaming, then you are basically wrong about such experiences - they are not really happening. And if you are dreaming, it makes no difference how you treat people (they aren't real), so there are ethical considerations. Related to dreaming is the famous "brain in a vat" problem; if scientists are able to keep a brain alive, and to stimulate it with simulated sights and sounds, well, how do you know this is not happening to you right now? If you object that scientists can't do that with current technology, then how do you know they are not doing it two hundred years from now and feeding you stimulation that makes it seem as if you are in 2012? And hit the simulations up a notch: what if you and everything around you are just a simulation in a game? What if you are just a slower and less exciting version of Lara Croft? We can't simulate a full world include Lara Croft (and others) with consciousness right now, but maybe they will be able to do so in the future, and maybe they are doing that in the future and it only seems like right now. You can hunt through the chapter "Dreams and Simulations," and you won't find reassuring tests to tell you that such things absolutely cannot be.
The second chapter, "Is Matter Real?" brings up the five definitions, and naturally Bishop Berkeley's idea that all we have are perceptions of things "out there," not the things themselves which remain inaccessible. If so, says Westerhoff, "The reality of matter is a hypothesis we can do without." Berkeley's concept is important in the history of philosophy, but one of the attractive parts of Westerhoff's work is that it is not composed entirely of ivory-tower philosophizing. The problem of the reality of matter has become complicated by science, and Westerhoff summarizes the paradoxes essential in matter being both (and neither) a wave or a particle. This may turn out to mean that reality is at bottom a complicated array of mathematical sets (liable for computer simulation, to be sure). The quantum world might be real, but if so, it depends upon objects like ourselves and our measuring devices to show it, and such objects depend on quantum objects within them; if so, there is no way out of the circle, and no "rock-bottom" reality to matter.
"Are Persons Real?" presents further scientific investigation, this time about the self. Your impression of your own real existence might be modified. Amputees, for instance, often get a phantom limb syndrome, with all the feeling that they still have a real limb long after it has gone. Experimentally you can be fooled to think someone else's hand (or even an inflated surgical glove) has sensations you perceive as your own. What is the meaning of self if it does not know even those basic realities for sure? Your brain is busy constructing a self for you, but it can't be a real self. For instance, it can be shown that the processing speed for vision and for hearing is different, and also light and sound take different times to get to us; nonetheless, the brain processes most such stimuli to make them seem simultaneous, even if they are not. There are experiments, too, that show that what we think of as our free will can be modified by passing magnetic stimulation through portions of the brain; subjects think they are making their own choice, but the magnetic stimulation influences it, so where is the self in such choices?
In a final chapter, "Is Time Real?" Westerhoff confronts (though does not quote) the child's objection, "How can today be today when tomorrow today will be yesterday, and yesterday today was tomorrow?" Naturally, he takes us briskly through the paradoxes of relativity, where one person's "now" may not be that of another person, even if they are watching simultaneous events. We can accept that the present is real, or at least more real than the past which is no longer with us and the future which is yet to come. It will not surprise you to learn that Westerhoff shows that the present is actually pretty slippery, harder to pin down than the past or future. When exactly the present is we cannot say; the present moment is subjectively important to us, but if our sense organs take different times to present stimuli to us, what is that moment? Is it manufactured by the brain? Experiments can be performed to show that although event A comes before event B, the brain may be manipulated to experience them in the reverse order. Even without performing temporal illusions on brains, the "delayed choice experiment" in quantum physics shows that causality seems to work backwards.
This is the most disturbing little book I have read in a while. The arguments throughout the book are no mere sophistries, but Westerhoff keeps things light. He has a good sense of humor, and knows how strange it is to contemplate what he is describing. He has lots of questions but any answers at which he might hint raise further murky issues that have no answers yet. I finished this entertaining and perplexing book wondering how, if reality itself is so iffy, we can know anything at all. Perhaps we must invoke Firesign Theater again: "Everything you know is wrong."