A familiar teaching about Socrates, based mostly on Plato's representation of the Athenian philosopher, is that he professed not to know anything. The only thing he knew, he is reported to have said, is that he knew nothing.

Yet this teaching is fraught with paradox because while it professes knowledge of nothing, it is itself a claim to knowledge, self-knowledge, the knowledge that one is ignorant of everything. Everything? But if so, then how could Socrates know of his own ignorance, given that his ignorance clearly is a candidate for something to be known?

Perhaps there is a solution to the paradox, a resolution to what appears to be a conflict in Socrates' position. Suppose that there is a kind of knowledge that Socrates, or anyone else lacks, namely, knowledge that is absolute, incorrigible, without the possibility of ever being modified, changed, updated. Suppose this is a kind of knowledge that Socrates does indeed lack. In ordinary situations we run across mention of this kind of knowledge when someone challenges a claim we make to know something with the retort, ‘But are you absolutely sure of it? Are you completely certain?’ Say I tell you where my car is parked. You ask me, ‘Do you know that it is parked there?’ I tell you, ‘Yes, sure I do; I parked it there myself.’ But you come back with, ‘But are you certain, beyond any doubt, any possible doubt, that the car is there?’ And here I must admit that I am not certain like that. I am only reasonably certain – I know it beyond a reasonable doubt – not absolutely certain – certain beyond a shadow of doubt.

Which is the kind of knowledge we should understand Socrates to have disowned? Is it that absolute variety? Or the more modest?

I suggest that when Socrates claims he knows only that he knows nothing, he first uses ‘know’ in the modest sense, then in the more demanding one. And this seems to me a worthy thing to teach – few if any of us have that final, finished knowledge that some take the idea ‘know’ to mean. It is more reasonable to understand by ‘know’ the more modest notion that when one makes a claim to knowledge – say, to know where one's car is parked – one is only claiming to know beyond a reasonable doubt. This is what I believe we learn from J. L. Austin's famous paper, ‘Other Minds’ as well as from Ludwig Wittgenstein's posthumously published book, On Certainty.

It is good to keep in mind that the absolute type of knowledge probably doesn't exist, not for human beings at any rate, since none of us can tell at any given time that what we know will not in some future time require some modification, adjustment, editing. Yet why should one be disturbed about this? Why contend, as Socrates appears to do, that this is inferior knowledge? It is indeed the knowledge that is produced in all the sciences, in philosophy and ordinary life. That other kind is at best an imaginary-Disneyland-type of knowledge, a myth, even, and no one need apologize for not having it. It is not the object of human inquiry but of human fantasy.

So what Socrates must have meant by claiming to know nothing is that he doesn't know anything in that fantastic fashion, for absolutely, timelessly, and incorrigibly certain. But he knew this, so he did in fact know something. But this he knew in the sensible way, the way human beings know a great many things. He knew that he had no final, perfect, timeless knowledge. And he was right – none of us does. There is no such thing, no such knowledge! And it is a valuable lesson Socrates taught when he told us this fact, a fact he knew and he must have assumed we all can know as well and perhaps even benefit from knowing.