Philosophical Bits #2:
Skepticism
But how do I know “this is real”? Epistemology tries to answer the question: How do I know? Related questions: What is knowledge? What distinguishes knowledge from mere belief, even true belief?
Everyone agrees we would rather have true beliefs than false beliefs. But a true belief is not the same thing as knowledge. In the Meno, Socrates points out that some people may adopt a belief, a belief which turns out to be true, without good evidence or by bad reasoning. They might believe something merely because their hated enemy doesn’t believe it or because no one has proved it false. They might fall into a belief by accident. Mere true belief is not enough, says Socrates. We know when the truth of our belief is tied to the belief by the “bonds” of good reasons.
This traditional answer, that knowledge is justified true belief, received scrutiny in the 20th century. In 1963 Edmund Gettier published a short article, “Is Justified True Belief Knowledge?” in which he gives examples of persons who believe a proposition for good reasons (so the belief is justified), and the proposition is in fact true, but do not seem to be cases of knowledge. Other philosophers quickly created more examples. Here’s one: While driving in the Willamette Valley, Debbie sees what looks to be a sheep and forms the belief, “There is a sheep in that field.” In fact, the animal she sees is a dog wearing a sheep outfit made by a middle-school student as part of a prank. However, unknown to Debbie, there is another animal, a real sheep, standing in a portion of the field but hidden from her sight by a large sign. Debbie’s belief is true (there really is a sheep in the field), and her belief is justified (she sees an animal that looks like a sheep), but it seems that her justified belief is true only by accident. It seems her justified true belief isn’t knowledge.
Philosophers have tried to repair their understanding of knowledge in a variety of ways. I won’t discuss the details. In general, the answer to Gettier problems is that justification must hook up to the true belief in the right way. But the devil is in the details. What is the right way? Disagreement persists on that score.
Skeptics watch from the epistemological sidelines, as it were. The players in the epistemology game strive to define knowledge, with the goal of better guiding our pursuit of knowledge. The game is pointless, say the skeptics. Knowledge is a chimera. Epistemology might produce some guidance about the way we adopt or reject beliefs, but we should abandon the hope of attaining knowledge. Regarding any particular belief, the skeptics say, we must face the truth: we might be wrong.
What about science? Four centuries of modern science have dramatically changed our beliefs. Technology, based on scientific discoveries, has dramatically changed our practical world in thousands of ways: electricity, telephones, antibiotics, plastics, radio, Internet, blood transfusions, cars, telescopes, airplanes, microscopes, genetic tests, photographs, videos, recorded music, man-made fibers, and so on. Surely science gives us knowledge, and the knowledge given by science has made technology possible.
The skeptics say no. Science gives us new beliefs. Technology based on those beliefs has changed our practices. But are we guaranteed those beliefs are true? Do we have knowledge? No. We might be wrong.
20th century skeptics were certainly aware of modern science. The scientific method combines empirical observations with theories. We propose the theories to make sense of the observations, and we use further observations to test the theories. Therefore, some philosophers said (these philosophers identified themselves as “positivists”), empirical observations must lie at the heart of science. Scientific and philosophical theories are meaningless, the positivists said, unless they can be verified empirically. A.J. Ayer’s 1936 book, Language, Truth, and Logic is an enthusiastic presentation of positivism by one of its exponents. According to Ayer’s “verification principle,” all meaningful statements are either tautologous or verifiable (at least in principle).
Now, the verification principle is self-referentially incoherent. It is itself neither tautologous nor verifiable. In the second half of the 20th century, philosophers rejected it. Along the way, though, positivism taught an important lesson.
Positivism inspired a conceptual search for pure empiricism, empirical observations untainted by theory. What would an “observation statement” look like? Obviously, if you use a scientific instrument like a telescope, all your observations must be qualified; you didn’t simply look at the stars, you looked at them with this instrument, with a specific description, and that description implicitly drags in a host of assumptions about light, mirrors, the construction of the telescope, and many other things. And in everyday scientific practice, that’s fine. But if scientific theories are to be tested by observations, at bottom we need some observations that are theory-free. What would “pure” observation be like?
For a decade or two, in the middle of the century, positivist philosophers of science tried to conceptualize theory-free observations. By the time positivism collapsed (because of its self-referential incoherence), philosophers of science had adopted a truism: there are no theory-free observations. All our empirical observations are loaded with assumptions.
Does this mean we don’t have knowledge? Are the skeptics right?
For example, can we know that everyday empirical experiences yield truth? Is the grass really green? (Fido doesn’t see color. Is color real?) Is there a tree over there? Should I modestly say only that it seems to me that there is a tree over there? Some skeptics would say I know only that it looks like a tree to me; the world outside my mind may be different than what I perceive.
Can we know that other people have minds? I might know that I have a mind, by direct experience. But can I know that other people have minds, that they are not cleverly designed robots? The skeptics would say we can’t know these things. After all, maybe the world was created five minutes ago by an evil demon who made the world just to deceive me. For all I know, the whole world is just a figment of my imagination, and everything other than my mind is nothing more than an item in my mental universe. Against the skeptics, G.E. Moore published a paper in 1939, “Proof of an External World.” In a public reading of the paper, Moore held up his hand. “I know this is a hand,” he said. “And here is another.” Since Moore and his audience both know these two things, there must be a world external to their minds.
It is said, perhaps apocryphally, that Ludwig Wittgenstein told Moore this paper was the best thing Moore had written. Wittgenstein certainly wrestled with the problem. A collection of his notes, written in the last months of his life and called On Certainty, begins: “If you really do know ‘Here is one hand,’ we’ll grant you all the rest.”
On Certainty is not a polished book, but a collection of notes, published after Wittgenstein’s death in 1951 by his literary executors. Philosophers have struggled with it ever since. My own notes on On Certainty are almost as long as On Certainty.
Wittgenstein thought something had gone wrong on both sides. The skeptics want to say we don’t know everyday facts that we observe or remember. Moore wanted to insist that he did know he had two hands, and his audience knew this as well. Wittgenstein thought both sides had lost touch with the “language game” of knowing.
The meaning of language is in its use, Wittgenstein wrote in Philosophical Investigations. How do ordinary people talk about knowledge when they are not wrestling with skepticism? When would we, in real life, say, “This is a hand”? The language game of knowing includes things like doubting and being sure.
Example. Bob asks, “Did you go to the club Thursday?” Sally replies, “Sure. I always go.” Bob: “But they moved the meeting last week.” Sally: “Oh! That’s right. I forgot. I went to the meeting Wednesday. But I also went to the club Thursday. I know I did because I had to return a book.”
This is an unremarkable use of “know,” completely at home in ordinary language. Both the skeptic and the commonsense realist (Moore) are tempted to take knowing away from such examples. I think Wittgenstein praised Moore’s essay because “Proof of an External World” shows how the skeptics had gone too far. But he worried that Moore’s refutation—“I know this is a hand”—was also language gone on holiday.
Perhaps the best answer to skepticism is that we live this way. We live in a world where water boils at 100 degrees Celsius and freezes at 0 (an example in Wittgenstein’s notebook). We are confident that the world of my morning walks is real, but the world of my novel is not. We cannot “refute” the extreme skeptic, but we live this way. And the skeptic is one of us.
