It happened in the middle of an argument I have had many times, with someone I have known most of my life.
We were well into it — the same disagreement we always have, in the same familiar form — and I was doing what this show has taught me to do. Building my case. Listening closely. Watching their face for any sign the argument had reached them.
And then, for a second or two, I was disoriented. Not in the way you are when you can feel you are losing an argument. Something different. I looked at their face — a face I have known for decades — and I thought: I have no idea what it is like in there. I am sitting eighteen inches from this person, closer to them than to almost anyone alive, and I cannot get to the inside of their experience. I can see the face move. I can hear the words. But the life on the other side of that face, the having of it from the inside, I have never once had access to, and I never will. I have been inferring it. I have been inferring this whole person, every day, for thirty years.
And here is what made it more than a passing thought. In the same moment two fears arrived together, and they seemed to belong to each other, though I could not have said how.
The first fear I knew well. It is the one this whole series has been about: that I was never going to reach them — that I could argue until morning and the distance would hold.
The second fear was new, and colder. It was not I can't reach them. It was I can't even be sure there is a "them" to reach. That for all my careful arguing toward the person across the table, I had never actually confirmed that anyone was there. That for thirty years I had been taking it on trust.
Two fears, one moment. I will never argue my way across to them. And I cannot even know they are really there. They seemed related. They seemed to come from a single source. And I have spent a long time since trying to work out what that source is — because it turns out to be the thing this show has been returning to all along.
This is Philosophy for Us — philosophy for everyone, no degree required. This is the fifth of eight episodes — the last series this show will make — about the edge of argument: the place where you have made every case you have and the other person still has not crossed.
Last time, we rejected the cynic. He made his strongest case: past the limit of reason, he said, there is nothing left but preference and power — two wills in conflict, and the stronger one wins. We refused him, and we did it without retreating to the hope that more argument would settle things. He had slipped in one unargued step: he moved from there is no fact at the bottom to therefore there is only force at the bottom. And that silence with the person you could not dismiss was not, when you actually stood inside it, two wills in conflict. So we closed off the cynic's answer as well. That left both easy answers ruled out and a third thing in front of us that we could not yet name.
Tonight we begin to name it. And the help comes — as I promised it would — from that second fear itself, from the doubter who says you cannot even know there is another mind behind that face at all. I am going to bring him in at full strength, and at first he will seem to have nothing to do with our problem — an academic curiosity, a clever nuisance. Then I am going to show you that following him, of all people, is what makes the difference. The difficulty is that what he reveals, he reveals first about you — about something you have been doing this entire series without noticing.
Let me bring the doubter in, and let me do it properly — at full strength, the way we have taken on every serious opponent this series. Your first instinct will be to dismiss him as an undergraduate provocation, the sort of thing a clever teenager says at two in the morning. He is not that. He is the most radical doubter in philosophy, and in twenty-five hundred years no one has cleanly answered him.
Here is what he says. Set aside, for a moment, the people you disagree with. Take the person you are closest to — the one whose inner life you would say you know better than anyone's. And let me ask a plain, almost rude question: how do you know there is an inner life in there at all?
You will want to say: obviously there is, I can see it. But look at what you actually have. You have your own mind, and that one you have from the inside, directly, with no inference. You do not conclude that you are in pain; you simply hurt. You do not gather evidence that you are happy; you are happy. But every other mind in the universe you have only ever met from the outside. You have the face. You have the words. You have the behaviour — the wince, the laugh, the catch in the voice. And from all of that outside, you infer the inside. You have never once had the inside itself. You cannot get to it. There is no vantage point you can move to, no test you can run, no instrument you can build, that would take you from the outside of a person to the inside and confirm that someone is there.
And the inference is not airtight. It cannot be. Everything you can observe from the outside — every word, every change of expression — could in principle be present with no one behind it. And you know this, because you have seen it happen. The person who smiles and means none of it. The performance so good you could not tell it from the real thing. The grief that turns out to have been an act. The sceptic simply takes that ordinary experience and follows it to its end: if a perfect performance is even possible — if the outside can come apart from the inside even once — then the outside is never proof of the inside. It is evidence. Good evidence, usually. But evidence is not the thing itself. And about the one matter you would have called yourself surest of in all the world — that the people you love are real people, with real inner lives, that there is someone there — you have, strictly speaking, never had proof. You have had trust, and habit, and a lifetime of evidence that falls just short of certain.
And it is not only other people. The same doubter applies the same doubt to the whole world. Everything you call "the world out there" reaches you only through your own senses — which is to say, from inside your own head. You have never stepped outside your own experience to check that there is a world matching it; you could not, because every check you ran would itself be one more thing happening inside your experience. Perhaps there is a world. Almost certainly there is. But you cannot prove it from where you sit. A dream you do not yet know is a dream looks exactly like waking, from the inside. So the external world stays open too, as a question you cannot close.
Now, be careful here, because it is easy to hear all this as a nuisance — a riddle with a trick answer that someone will supply in a moment. It is not that, and I am not going to supply a trick answer, because there is not one. Look at the actual situation, because it is stranger than the nuisance version suggests. You go through your entire life certain — and rightly certain, I would say — that other people are real and the world is real. And that certainty has never, for one second, rested on proof. It cannot. So the doubter has not shown you that you are wrong to be certain. He has shown you something stranger: that your certainty was never the kind of thing proof delivers in the first place. You have been living, the whole time, in a relation to other people and to the world that resembles knowledge and cannot be reduced to it. That is the thing to hold on to, because everything tonight builds on it: your deepest certainties are not built out of proof. They never were.
So that is the doubter, at full strength, and I am going to leave him standing — because, I will say it again, no one answers him, and I am not going to pretend to tonight. But here is where he stops being an academic curiosity and starts being about you. Because he looks like he belongs to a completely different discussion. What has "can you prove other minds exist" got to do with two people stuck on opposite sides of a table? Everything. Because he has a counterpart. And you have already met the counterpart. In fact — and you may not like this — for more than forty series, this show has been carefully training you to be it.
Here is the counterpart. All series — for years — this show has been training one reflex into you, and by now it is so deep you have stopped noticing it is a reflex at all. The reflex says: when there is a distance between me and another person, that distance is a gap, and a gap is the kind of thing you close by knowing — by reasoning, by argument, by getting it right. A disagreement that survives my best argument is not a different kind of thing; it is the same kind of thing, only unfinished. One more good argument and I would be across.
That is you. That is the exact person this series set out to build. Let me give him a name, so we can keep him in view: the rigorist. The one who believes, all the way down, that the distance between two minds is a problem of knowledge — and that problems of knowledge give way to more and better reasoning, if you are honest and you do not quit.
Now set the rigorist beside the doubter, and look at them together. At first they could not seem more opposed. The rigorist is the optimist: keep going, you will get there. The doubter is the pessimist: give up, you cannot get there, you cannot even prove there is a far side to reach. One is full of hope, the other full of despair. Opposite moods, opposite verdicts; they would want nothing to do with each other.
But listen to what they agree on, underneath the moods. Both take it for granted that our relation to another person is supposed to be knowledge. Both assume that the right way to be connected to another mind is to know it — to have it the way you have a proven fact, with certainty, no gap left over. The rigorist assumes exactly that and concludes: good, then I will get there by arguing harder. The doubter assumes exactly that and concludes: then we are lost, because you never can. Two opposite conclusions, drawn from one and the same buried assumption. They are not enemies. They are one assumption in two forms. And the assumption neither of them stops to question is a single sentence: to be truly connected to another person is to know them with certainty — and any distance short of certain knowledge is a failure.
Start with the doubter, because he is the easier one to catch. Give him his due first: he has found something real. Proof really does fail here — you genuinely cannot get the airtight certainty about another mind that you can get about a sum. He is right about that, and no one is going to take it back from him. So his error is not the discovery. It is what he does with it. He came to other people holding a demand — you must give me certainty, the proof-grade kind — and other people could not meet it, because certainty was never what they had to offer. And instead of stopping to ask whether the demand made sense in the first place, he kept the demand and delivered the verdict: cut off, unreachable, cannot be known. The failure he found is real; his despair is an interpretation of it — the sound of a demand going unmet, of someone who asked for the wrong thing and then blamed the world when it could not provide it.
Now the harder half. Look at the rigorist the same way. At yourself.
When you sat at that table, and the argument ran out, and the person was still on the far side — and you thought, the way this show trained you to think, I just have not argued well enough yet; one more honest attempt and I would have them — what were you actually doing? You were holding the sceptic's demand. The identical one. You were treating that person as something you were supposed to be able to know your way across to: a problem with a solution you had not yet found. And when they did not yield to your reasoning, you questioned the demand no more than the sceptic did. You made the optimist's version of his move. Not "I am cut off" but "I am not finished." The same assumption underneath. The same picture of what connecting to a person even is. You simply happened to be standing on the hopeful side, where the despair does not show.
So here it is plainly, and I will not soften it. The doubter you were ready to dismiss as a student's game — he is you. Not your opposite. Your reflection. The faith this show built into you — argue well enough and you will close any distance — and the despair you would have sworn was its enemy — you cannot really know another mind at all — are the same move in two different moods. Optimism and despair about one impossible demand: that the way to have another person is to know them, with certainty, the way you know that two and two make four.
Which leaves one question, and it is exactly the right one to ask next. If both the hope and the despair rest on this single demand — that real connection has to be certain knowledge — then where did the demand come from? Because it does not feel like an assumption. It feels like plain truth, something too obvious to examine. But the things that feel most obvious are exactly the ones worth examining — you learned that on this show, some time ago. Every settled fact you carry, we said, is really a standpoint, and every standpoint has a history you can uncover. We ran that test on all sorts of things. We never once ran it on this — on the show's own deepest faith, that reasoning is how minds reach each other. So let us run it there now. Let us find out when, exactly, human beings began to believe that to be close to something was to know it.
So we are going to do what this show has taught you to do with any idea that feels beyond question: find out when it began. Because this demand — that real connection means certain knowledge — has a beginning. It is not how human beings have always thought. It is a few hundred years old, and you can almost watch it take hold.
Go back before it. Before the modern age, the way a person was bound to the world and to other people was not modelled on proof at all. Your tie to the people around you — to your family, your dead, your town, the world itself — ran through your place among them. You belonged to a household, a village, a faith, a trade. You were with people, and turned toward them, long before you were ever a lone mind sitting in judgement, weighing the evidence for whether they existed. No one sat across from their own child and felt they had a problem of knowledge about whether a mind was in there. The relation was not a conclusion you reached from evidence. It was the ground you already stood on, before any arguing began. You took part in the world before you ever thought to question it.
And then something changed, and we can put a name and almost a date to it. About four hundred years ago, a philosopher sat alone by a fire through a long winter and set out to doubt everything he possibly could — to doubt his way down to whatever, if anything, was left standing. He found he could doubt the world: perhaps it is all a dream. He found he could doubt his own body, doubt other people, doubt nearly everything he had believed. But there was one thing he could not doubt: that he was thinking the doubt. Even to doubt, he had to exist, doing the doubting. The line his whole project is remembered by, the one you have heard even if you have never read him, is: I think, therefore I am. And on that single certain point — the thinking self, alone, sure of itself from the inside and of nothing else yet — he set out to rebuild the whole of human knowledge, step by proven step.
His name was Descartes, and whether or not you have ever read a word of him, you have inherited what he did by that fire. So look closely at what it does, because it is still at work, in you, tonight. Before Descartes, the self was in the world, among others, taking part. After Descartes, the self is a mind alone in a room, certain of one thing — its own thinking — and facing everything else as a question to be answered from in there. The world outside: a question. Your own body: a question. And the other person, the mind across the table: a question. Everything that used to be the ground you simply stood on becomes, instead, a problem to be proved — proved from the inside out, starting from the one thing the mind is sure of, which is only itself.
And here is the cost of that move, a cost that is not felt for centuries — that is felt, in fact, by you. Once knowing-with-certainty becomes the standard — once the only fully respectable way to be related to anything is to have proved it from the inside — then everything you cannot prove that way begins to look like a failure. And you cannot prove the external world that way. You cannot prove other minds that way. We spent the whole first part of tonight watching that you cannot. So the permanent, built-in fact that you can never get certainty about the people across from you — which, before, was no problem at all, because closeness was never about certainty — now looks like a disaster. A gap that should not be there. Something that ought to be closable and stubbornly is not. That is the sceptic's despair, and now you can see what it really is: the Cartesian demand, presenting its cost. The doubter is Descartes' grieving heir — still wanting the certainty the lone mind was promised, still unable to get it about the people he loves, and calling that a tragedy.
But here is where you uncover the thing about yourself, so do this part yourself. The sceptic is not the only heir. Look what else follows from that same move. If the other person is a problem to be proved from the inside out, then there are exactly two ways to feel about a problem you cannot yet solve. You can decide it is unsolvable, and despair — that is the sceptic. Or you can decide it is merely unsolved so far, and set to work — and that one is the rigorist. That is the whole confidence of the modern age in a sentence: the world is a set of problems, and method — careful reasoning, applied hard enough and long enough — is how we solve them, one after another, without end. The optimism that built the modern world and the despair of the sceptic are the same inheritance, divided into a hopeful child and a hopeless one. And this show — for more than forty series, every time it taught you to reason honestly to the bottom of a thing — was raising you, with the best intentions, to be the hopeful child. The rigorist is only the sceptic who has not yet given up. The same demand, the same picture, the same lone mind by the same fire.
So when you sat at that table and reached, by trained reflex, for I just need to argue this better — that reflex was not the neutral, obvious, only-sane response it felt like from the inside. It was a four-hundred-year-old standpoint, presenting itself as plain common sense. One particular bet about what other people are — problems to be solved — handed to you so early and so completely that you mistook it for simple fact. And you have just uncovered its history yourself. Which means the reflex can never again feel like simply seeing clearly. It feels, now, like what it is: a choice. One you did not know you were making. And that raises the only question left tonight — the one the whole series has been approaching all this time without ever saying it aloud. If reaching for the argument is a choice, what is the other choice?
Let me give you the other choice as plainly as I can. And then I am going to be honest that naming it is not the same as understanding it — and the understanding is next week's whole work.
Here is the situation, put simply. You are at the table. You have argued all the way to the bottom. The person is still on the far side. The argument is genuinely over — over, not paused. And in that silence, the four-hundred-year-old reflex offers one word: unfinished. Treat them as a problem your reasoning has not yet cracked. Treat the whole thing as unsolved business, and either keep working at it or, on a worse day, drift toward the sceptic and despair that you are simply cut off. That is one move. And after tonight you can see that it is the only move the picture knows — both of its moods, the working and the despair, are the same move.
But there is another thing you could do in that silence, and the whole weight of tonight rests on this being genuinely another thing, not a gentler version of the first. You could stop treating them as a problem to be solved, and treat them instead as someone you were never going to solve. Not because you gave up on the problem — because they were never a problem in the first place. The distance between you was never a gap in knowledge waiting on a proof. It was the plain, standing fact of another person, as real and as separate as you are, sitting on the other side of a table. And that is not something you know. It is something you meet.
So here is tonight's question, put as plainly as I can. You have spent all this time — every episode, every argument, all that training — believing that if you just reasoned well enough you would get there. So notice what you actually do, the next time the argument runs out and the person is still standing across from you. Because there is a choice in that silence, and no further argument can make it for you. You can treat them as a problem your reasoning has not yet solved. Or you can treat them as someone you were never going to solve. The arguing brought you all the way here, to that choice — and then it goes quiet, and the choice is yours.
There is a philosopher who gave his whole life to exactly this, and I will give you his name now, because we will be with him next week: Stanley Cavell. Cavell gives us a name for it — a diagnosis, not a verdict to take away tonight, and one we will spend the remaining weeks testing. Here is roughly how it runs. The sceptic, Cavell says, was never really making a discovery about the limits of knowledge. The sceptic was refusing acknowledgement — and dressing the refusal up as a failure of knowledge. "I can't know you are really there" is what it sounds like from the outside. But underneath, it is closer to this: "I will not — or I cannot bear to — simply acknowledge you, meet you as real, without the safety of a proof first." The sceptic takes a person he could have acknowledged and turns them into a problem he cannot solve — because a problem keeps him at a safe distance, and a person does not. And the same can be true of the rigorist. Of you. When you reach for one more argument rather than face the person in front of you, "if I just reason hard enough I will get there" can become a way of not acknowledging someone — of keeping them a problem you are nobly still working on, so that you never have to do the other thing, the one with no proof in it, and simply meet them.
Now — be clear about what I have and have not done tonight. I have not told you what acknowledgement is. I have told you what it is not: it is not knowing. I have shown you that your most trusted reflex — the one this show itself gave you — is one side of a four-hundred-year-old inheritance, and the sceptic's despair is the other side, and that neither one is the plain, neutral truth about how people are joined to each other. That is what you have tonight, and it is a strange, unsteady thing to hold. You walked in with one reflex that felt like clear sight — the distance is a gap; close it by reasoning — and you leave still able to use it, because most of the time it is right and I would never take it from you. But you can see it now. You can catch it the moment it fires. You can see, perhaps for the first time, that it is a choice and not simply the way the world is — and that there is a choice here the arguing was never going to make for you.
This is the fifth of eight, and the fifth of this show's last. This changed for me the first time I understood it. But look hard at what I have not handed you. I have not told you what to put in that gap. I have given you a name — acknowledgement — and a name is not the same as understanding. You have the name; the understanding is still ahead.
And next week we take it up — carefully, because the moment I say "acknowledgement", your mind will fill the blank with something soft and almost exactly wrong. You will hear: be kind. Accept people. Stop all this arguing and just connect. The greeting-card version. And that is nearly the opposite of what Cavell means. The short version, the part you can carry tonight, is only this: it turns out to be harder than knowing, not softer. What that means, and why, is next week's whole work — and I will approach it from the most unlikely source I could choose: a father, a daughter, and the most famous test of love in the English language.
But that is next week. Tonight, do not step back now. Take the disagreement you have been carrying all series — the real one, the person you cannot write off. Find the moment, and you have one, where you quietly filed it away as they just have not seen it yet; one more good argument and they would come around. Now look at that moment with what you uncovered tonight. That reflex — is it really clear sight? Or is it the hopeful version of the very same stance whose despairing version is I could never really reach them at all — both of them treating that person as a problem to be solved, when perhaps, the whole time, they were never a problem? I am not going to tell you which. That is the one thing the method cannot do for either of us. But here is the question to carry, and notice that it is a different question from the one you walked in with. You used to ask: why can't I get across to them? Tonight the question turns into something sharper, and harder, and much more honest. What if getting across was never the thing I was supposed to do — and the silence on the far side of the argument was never a gap in what I know, but a choice in what I am willing to face?
Do not answer it tonight. You do not have the thing itself yet — only its name, and that there is something there to understand. Stay with the question. We take it up next week.
Thanks for listening. I'll see you next time.