[From Bill Powers (2007.02.14.0750 MST)]
Richard Kennaway (2007.02.13) --
Surely science is the path that avoids both naive realism and solipsism?
Naive realism doesn't work, because it's very easy to demonstrate that however things work, they do not work the way we might naively take them to.
Which is only to say that what our formal observations, theories, and models tell us about how things "really" work does not conform to what our unaided senses and informal reasoning tell us (unfortunately, we have to use our unaided senses to know what the instruments are telling us, and our informal brains to think about them, so we still don't know what the instruments are really telling us).
Visual illusions show that we cannot take what we see to be reality itself.
That is, unless the crossbars of Ts really do get shorter and longer as the T is turned, and there really is an alternate universe for each of us so each sees a different reality (see quantum physics fantasies).
The demonstration in which one puts one hand in cold water, one in hot, and then both in tepid, whereupon the tepid water feels simultaneously hot and cold, shows that our sense of temperature is not directly telling us something about the objects we touch.
Only under the assumption that the same thing can't be both hot and cold. I'm happy to make that assumption, but that's all it is. Nobody can force me to make it.
Naive realism has to be discarded as soon as one tries to find out how things work.
On the contrary, finding out how things work means making models under the assumption that naive realism should be dropped and reality is not exactly and only what we experience. The cart comes _after_ the horse.
Our perceptions turn out to be physical phenomena with no intrinsic meaning. They are sometimes closely but sometimes distantly related to the things we naively took them to be giving us direct access to.
This isn't doing it for me. I remain too conscious that all you are saying is the product of a human brain -- or rather, that if I were saying it, it would still be a product of my (presumed) brain, and uncheckable. When you speak of what "our perceptions turn out to be", are you saying "what our perceptions _really are_?" Really? Tell me how you know that, and this discussion will be finished.
Solipsism fails to account for the fact that we find ourselves having sensations that we cannot predict. To say that nothing but myself exists is just redefines the word "me" as meaning all of existence. It leaves unanswered the question of why we have the sensations we do. So does the speculation that we're all living in a simulation.
I think that there is excellent indirect evidence that there is something external to me. Overwhelming, incessant waves of evidence. But that's all it is, evidence, meaning perceptions. It is not the thing itself. So all still depends on my own human perception and reasoning. If I convince myself that I know there is a reality, I can't forget that I had to convince myself -- reality did not thrust itself on my awareness in the same way perceptions do. I can't become unaware that I wanted to know reality, and that to satisfy that want, I found premises and a train of reasoning that would end with that desired conclusion. That is not discovery, it's invention.
As you've often pointed out, we can't get outside of ourselves and all we have to work with is our perceptions. Science works better than anything else at making sense of them. What more is needed?
Nothing -- if you just want to drop this problem and get on with life. I wouldn't blame anyone for doing that. Of course then you would have to forget that you dropped the problem and that it remains unsolved. Don't think about that white elephant in the dining room.
Now, maybe we are as if shut up in a dark cell, our feeble senses and actions like to tapping on the pipes and hearing noises come back, and all the while there are vast, unknowable realms of reality outside and forever beyond our grasp, but to me that's just a speculation that it's entertaining to weave some purple prose around. Given the vastness of just the universe we know of and the minuteness of our presence in it, it could even be true.
Well, perhaps you have just explained why you would prefer to drop the problem. If you suspect that those rather chilly thoughts might be the truth, I can see why you might not want to forge ahead and find out that you are right. But what if you are wrong?
I have difficulty saying what I am looking for here. I think it may be a form of _reductio ad absurdum_, a way of showing that the idea of an unknown and unknownable reality contradicts itself and is therefore false. This would put an end to the cycle of "Yes, but that, too is only a thought." I would't be going on endlessly about this if I didn't have a feeling somewhere way in the background that there is a way to deal with this. Don't credit me with knowing what the solution looks like. I just think that ruling out self-contradiction may provide the key. You're the mathematician, not I. You're more likely to find the proof than I am. In a respectable tradition, I simply provide the conjecture. The margins are much wider than needed to hold any proof I could think of.
Best,
Bill P.