168 / Berkeley

Speaking of epistemology, one of my favorite philosophers is George Berkeley (pronounced Bark-ley). Click on the title link to read the Wikipedia description of his philosophical conclusions, which are sometimes called "subjective idealism." Berkeley said that human beings can know about "reality" only through "sensations," and their "perceptions," and that we can never directly connect with things themselves.

That observation has always seemed pretty much irrefutable to me, though it doesn't mean that the "things themselves," which we only know from our perceptions, and our ideas about them, don't actually "exist." In other words, the fact that we know about things only through the sensations that we experience, doesn't mean that the things we confront through our perceptions are illusions; they may, in fact, completely conform (in "reality") to the perceptions we have. The Wikipedia article describes a refutation of Berkeley's theory, by Samuel Johnson, as follows: "Dr. Samuel Johnson kicked a heavy stone and exclaimed, 'I refute it thus!'"

Seen from the perspective of the two-worlds hypothesis, the world of Nature, to which Johnson's stone belongs, is perhaps a different kind of reality from the reality of the world we create ourselves. In our world, the heavy stones we kick are not immovable or immutable, though our "perceptions" may suggest they are.