While I was still a boy, I came to the conclusion that there were three grades of thinking; and since I was later to claim thinking as my hobby, I came to an even stranger conclusion -- namely, that I myself could not think at all.

I must have been an unsatisfactory child for grownups to deal with. I remember how incomprehensible they appeared to me at first, but not, of course, how I appeared to them. It was the headmaster of my grammar school who first brought the subject of thinking before me -- though neither in the way, nor with the result he intended. He had some statuettes in his study. They stood on a high cupboard behind his desk. One was a lady wearing nothing but a bath towel. She seemed frozen in an eternal panic lest the bath towel slip down any farther; and since she had no arms, she was in an unfortunate position to pull the towel up again. Next to her, crouched the statuette of a leopard, ready to spring down at the top drawer of a filing cabinet labeled A-AH. My innocence interpreted this as the victim's last, despairing cry. Beyond the leopard was a naked, muscular gentleman, who sat, looking down, with his chin on his fist and his elbow on his knee. He seemed utterly miserable.

Some time later, I learned about these statuettes. The headmaster had placed them where they would face delinquent children, because they symbolized to him the whole of life. The naked lady was the Venus of Milo.

She was Love. She was not worried about the towel. She was just busy being beautiful. The leopard was Nature, and he was being natural. The naked, muscular gentleman was not miserable. He was Rodin's Thinker, an image of pure thought. It is easy to buy small plaster models of what you think life is like.

I had better explain that I was a frequent visitor to the headmaster's study, because of the latest thing I had done or left undone. As we now say, I was not integrated. I was, if anything, disintegrated; and I was puzzled. Grownups never made sense. Whenever I found myself in a penal position before the headmaster's desk, with the statuettes glimmering whitely above him, I would sink my head, clasp my hands behind my back and writhe one shoe over the other.

The headmaster would look opaquely at me through flashing spectacles.

"What are we going to do with you?"

Well, what were they going to do with me? I would writhe my shoe some more and stare down at the worn rug.

"Look up, boy! Can't you look up?"

Then I would look up at the cupboard, where the naked lady was frozen in her panic and the muscular gentleman contemplated the hindquarters of the leopard in endless gloom. I had nothing to say to the headmaster. His spectacles caught the light so that you could see nothing human behind them. There was no possibility of communication.

"Don't you ever think at all?"

No, I didn't think, wasn't thinking, couldn't think -- I was simply waiting in anguish for the interview to stop.

"Then you'd better learn -- hadn't you?"

On one occasion the headmaster leaped to his feet, reached up and plonked Rodin's masterpiece on the desk before me.

"That's what a man looks like when he's really thinking."

I surveyed the gentleman without interest or comprehension.

"Go back to your class."

Clearly there was something missing in me. Nature had endowed the rest of the human race with a sixth sense and left me out. This must be so, I mused, on my way back to the class, since whether I had broken a window, or failed to remember Boyle's Law, or been late for school, my teachers produced me one, adult answer: "Why can't you think?"

As I saw the case, I had broken the window because I had tried to hit Jack Arney with a cricket ball and missed him; I could not remember Boyle's Law because I had never bothered to learn it; and I was late for school because I preferred looking over the bridge into the river. In fact, I was wicked. Were my teachers, perhaps, so good that they could not understand the depths of my depravity? Were they clear, untormented people who could direct their every action by this mysterious business of thinking? The whole thing was incomprehensible. In my earlier years, I found even the statuette of the Thinker confusing. I did not believe any of my teachers were naked, ever. Like someone born deaf, but bitterly determined to find out about sound, I watched my teachers to find out about thought.

There was Mr Houghton. He was always telling me to think. With a modest satisfaction, he would tell me that he had thought a bit himself. Then why did he spend so much time drinking? Or was there more sense in drinking than there appeared to be? But if not, and if drinking were in fact ruinous to health -- and Mr Houghton was ruined, there was no doubt about that -- why was he always talking about the clean life and the virtues of fresh air? He would spread his arms wide with the action of a man who habitually spent his time striding along mountain ridges.

"Open air does me good, boys -- I know it!"

Sometimes, exalted by his own oratory, he would leap from his desk and hustle us outside into a hideous wind.

"Now, boys! Deep breaths! Feel it right down inside you -- huge draughts of God's good air!"

He would stand before us, rejoicing in his perfect health, an openair man. He would put his hands on his waist and take a tremendous breath. You could hear the wind, trapped in the cavern of his chest and struggling with all the unnatural impediments. His body would reel with shock and his ruined face go white at the unaccustomed visitation. He would stagger back to his desk and collapse there, useless for the rest of the morning.

Mr Houghton was given to high-minded monologues about the good life, sexless and full of duty. Yet in the middle of one of these monologues, if a girl passed the window, tapping along on her neat little feet, he would interrupt his discourse, his neck would turn of itself and he would watch her out of sight. In this instance, he seemed to me ruled not by thought but by an invisible and irresistible spring in his nape.

His neck was an object of great interest to me. Normally it bulged a bit over his collar. But Mr Houghton had fought in the First World War alongside both Americans and French, and had come -- by who knows what illogic? -- to a settled detestation of both countries. If either country happened to be prominent in current affairs, no argument could make Mr Houghton think well of it. He would bang the desk, his neck would bulge still further and go red. "You can say what you like," he would cry, "but I've thought about this -- and I know what I think!"

Mr Houghton thought with his neck.

There was Miss Parsons. She assured us that her dearest wish was our welfare, but I knew even then, with the mysterious clairvoyance of childhood, that what she wanted most was the husband she never got. There was Mr Hands -- and so on.

I have dealt at length with my teachers because this was my introduction to the nature of what is commonly called thought. Through them I discovered that thought is often full of unconscious prejudice, ignorance and hypocrisy. It will lecture on disinterested purity while its neck is being remorselessly twisted toward a skirt. Technically,it is about as proficient as most businessmen's golf, as honest as most politicians' intentions, or -- to come near my own preoccupation -- as coherent as most books that get written. It is what I came to call gradethree thinking, though more properly, it is feeling, rather than thought.

True, often there is a kind of innocence in prejudices, but in those days I viewed grade-three thinking with an intolerant contempt and an incautious mockery. I delighted to confront a pious lady who hated the Germans with the proposition that we should love our enemies. She taught me a great truth in dealing with grade three thinkers; because of her, I no longer dismiss lightly a mental process which for nine-tenths of the population is the nearest they will ever get to thought. They have immense solidarity. We had better respect them, for we are outnumbered and surrounded. A crowd of grade three thinkers, all shouting the same thing, all warming their hands at the fire of their own prejudices, will not thank you for pointing out the contradictions in their beliefs. Man is a gregarious animal, and enjoys agreement as cows will graze all the same way on the side of a hill.

Grade-two thinking is the detection of contradictions. I reached grade two when I trapped the poor, pious lady. Grade-two thinkers do not stampede easily, though often they fall into the other fault and lap behind. Grade-two thinking is a withdrawal, with eyes and ears open. It became my hobby and brought satisfaction and loneliness in either hand. For grade-two thinking destroys without having the power to create. It set me watching the crowds cheering His Majesty and King and asking myself what all the fuss was about, without giving me anything positive to put in the place of that heady patriotism. But there were compensations. To hear people justify their habit of hunting foxes and tearing them to pieces by claiming that the foxes liked it. To hear our Prime Minister talk about the great benefit we conferred on India by jailing people like Pandit Nehru and Gandhi. To hear American politicians talk about peace in one sentence and refuse to join the League of Nations in the next. Yes, there were moments of delight.

But I was growing toward adolescence and had to admit that Mr Houghton was not the only one with an irresistible spring in his neck. I, too, felt the compulsive hand of nature and began to find that pointing out contradiction could be costly as well as fun. There was Ruth, for example, a serious and attractive girl. I was an atheist at the time. Grade-two thinking is a menace to religion and knocks down sects like skittles. I put myself in a position to be converted by her with an hypocrisy worthy of grade three. She was a Methodist -- or at least, her parents were, and Ruth had to follow suit. But, alas, instead of relying on the Holy Spirit to convert me, Ruth was foolish enough to open her pretty mouth in argument. She claimed that the Bible (King James Version) was literally inspired. I countered by saying that the Catholics believed in the literal inspiration of Saint Jerome's Vulgate. The Latin Bible as revised in the fourth century AD by Jerome and used thereafter as the authoritative text for Roman Catholic ritual, and the two books were different. Argument flagged.

At last she remarked that there were an awful lot of Methodists, and they couldn't be wrong, could they -- not all those millions? That was too easy, said I restively (for the nearer you were to Ruth, the nicer she was to be near to) since there were more Roman Catholics than Methodists anyway; and they couldn't be wrong, could they -- not all those hundreds of millions? An awful flicker of doubt appeared in her eyes. I slid my arm around her waist and murmured breathlessly that if we were counting heads, the Buddhists were the boys for my money for one's money: according to one's opinion. But Ruth had really wanted to do me good, because I was so nice. She fled. The combination of my arm and those countless Buddhists was too much for her.

That night her father visited my father and left, red cheeked and indignant. I was given the third degree to find out what had happened. It was lucky we were both of us only fourteen. I lost Ruth and gained an undeserved reputation as a potential libertine.

So grade-two thinking could be dangerous. It was in this knowledge, at the age of fifteen, that I remember making a comment from the heights of grade two, on the limitations of grade three. One evening I found myself alone in the school hall, preparing it for a party. The door of the headmaster's study was open. I went in. The headmaster had ceased to thump Rodin's Thinker down on the desk as an example to the young. Perhaps he had not found any more candidates, but the statuettes were still there, glimmering and gathering dust on top of the cupboard. I stood on a chair and rearranged them. I stood Venus in her bath towel on the filing cabinet, so that now the top drawer caught its breath in a gasp of sexy excitement."A-ah!" The portentous consciously solemn or important. Thinker I placed on the edge of the cupboard so that he looked down at the bath towel and waited for it to slip.

Grade-two thinking, though it filled life with fun and excitement, did not make for content. To find out the deficiencies of our elders bolsters support the young ego but does not make for personal security. I found that grade two was not only the power to point out contradictions. It took the swimmer some distance from the shore and left him there, out of his depth. I decided that Pontius Pilate was a typical grade-two thinker. "What is truth?" he said, a very common grade-two thought, but one that is used always as the end of an argument instead of the beginning. There is still a higher grade of thought which says, "What is truth?" and sets out to find it.

But these grade-one thinkers were few and far between. They did not visit my grammar school in the flesh though they were there in books. I aspired to them, partly because I was ambitious and partly because I now saw my hobby as an unsatisfactory thing if it went no further. If you set out to climb a mountain, however high you climb, you have failed if you cannot reach the top.

I did meet an undeniably grade-one thinker in my first year at Oxford. I was looking over a small bridge in Magdalen Deer Park, and a tiny mustached and hatted figure came and stood by my side. He was a German who had just fled from the Nazis to Oxford as a temporary refuge. His name was Einstein.

But Professor Einstein knew no English at that time and I knew only two words of German. I beamed at him, trying wordlessly to convey by my bearing all the affection and respect that the English felt for him. It is possible -- and I have to make the admission -- that I felt here were two grade-one thinkers standing side by side; yet I doubt if my face conveyed more than a formless awe. I would have given my Greek and Latin and French and a good slice of my English for enough German to communicate. But we were divided; he was as inscrutable as my headmaster. For perhaps five minutes we stood together on the bridge, undeniable grade-one thinker and breathless aspirant. With true greatness, Professor Einstein realized that my contact was better than none. He pointed to a trout wavering in midstream.

He spoke: "Fisch."

My brain reeled. Here I was, mingling with the great, and yet helpless as the veriest gradethree thinker. Desperately I sought for some sign by which I might convey that I, too, revered pure reason. I nodded vehemently. In a brilliant flash I used up half of my German vocabulary.

"Fisch, Ja Ja."

For perhaps another five minutes we stood side by side. Then Professor Einstein, his whole figure still conveying good will and amiability, drifted away out of sight.

I, too, would be a grade-one thinker. I was irreverent at the best of times. Political and religious systems, social customs, loyalties and traditions, they all came tumbling down like so many rotten apples off a tree. This was a fine hobby and a sensible substitute for cricket, since you could play it all the year round. I came up in the end with what must always remain the justification for grade-one thinking, its sign, seal and charter. I devised a coherent system for living. It was a moral system, which was wholly logical. Of course, as I readily admitted, conversion of the world to my way of thinking might be difficult, since my system did away with a number of trifles, such as big business, centralized government, armies, marriage....

It was Ruth all over again. I had some very good friends who stood by me, and still do. But my acquaintances vanished, taking the girls with them. Young women seemed oddly contented with the world as it was. They valued the meaningless ceremony with a ring. Young men, while willing to concede the chaining sordidness of marriage, were hesitant about abandoning the organizations which they hoped would give them a career. A young man on the first rung of the Royal Navy, while perfectly agreeable to doing away with big business and marriage, got as red-necked as Mr Houghton when I proposed a world without any battleships in it.

Had the game gone too far? Was it a game any longer? In those prewar days, I stood to lose a great deal, for the sake of a hobby.

Now you are expecting me to describe how I saw the folly of my ways and came back to the warm nest, where prejudices are so often called loyalties, where pointless actions are hallowed into custom by repetition, where we are content to say we think when all we do is feel.

But you would be wrong. I dropped my hobby and turned professional.

If I were to go back to the headmaster's study and find the dusty statuettes still there, I would arrange them differently. I would dust Venus and put her aside, for I have come to love her and know her for the fair thing she is. But I would put the Thinker, sunk in his desperate thought, where there were shadows before him -- and at his back, I would put the leopard, crouched and ready to spring.