Chris writes > >>Samuel Johnson did refute Berkeley. > > The main thrust of Berkley's argument is to show that sensory perception is > indirect, and therefore the existence of a material cause for those > perceptions is an unjustified inference in contravention of Occam's razor. > The argument that the look, texture, smell, taste and sound of an object are > apprehended indirectly is successful in my opinion, and I don't feel any need > to defend it unless someone really thinks a defence is required.
Do *you* contend that the existence of material causes for your perceptions is unjustified? Good grief. As for your other statement, these senses are indeed, just as you say, apprehended indirectly. (That's the difference between realists and naive realists, e.g., children.) Of course there is no need for you to defend that, because no one here would disagree. > Afterall, on any view there is a translation of 'signals' of many > different forms (light waves, sound waves) , into various 'signals' > of the same form (neurons firing) which become synaesthetically > unified into a whole, such that we associate the smell, taste, > colour and texture of say an orange, as being qualities of the > same object. Of course. > ...Berkley's move here is to insist that it we have enough > information now to create the appearance of a 3 dimensional > world out of elements that are not intrinsically extended. I'm not sure what you mean. By elements already in the brain? Yes, that's true. But they got into the brain by the aforementioned processes, as you know. Don't lose sight of the fact that almost all the information came from outside. > By Occam then, we should not infer something for which there is no > requirement - however firmly that inference has been imbedded in us. > We should stick to using what we can know directly. Perception. You don't know all this complicated crap (neurons, perception, inference, the whole nine yards) nearly as well as you know the monitor in front of you. The problem is the word "know". The first things you knew consciously, and knew well, were things outside your skin: your mother and father, and tables and chairs. Let's resist the temptation to begin using words in other ways. Much, much later you ceased being a naive realist and became a realist. You understood that there can be things like optical illusions, and altered states of consciousness. You even understood that your own exalted consciousness is not anything to be utterly depended upon, because one can be sick or crazy. (If it hasn't happened to you yet, then just stay around a few more decades.) Build carefully upon what is simple and knowable, and keep the wild theories to a minimum. Even then, the world is hardly simple, but at least we've got a chance. > In other words, dualists and materialists contravene Occam, not > idealists. I don't see how Johnson refuted that. Materialists do not contravene Occam. The simplest explanation is that there is a world "out there" and that our brains are survival machines designed by evolution to thrive in it. The phantasms that occasionally infest our awareness and consciousness causally arise as side-effects of how our brains work, that's all. The simplest explanation does *not* start with perceptions and all the rest of that stuff, for a number of reasons. The primary reason is that you can't truly communicate them to others---after all, your brain may not work the same as theirs. As Wittgenstein said, "Of what we cannot speak thereof we must be silent". Lee
