…The present revolution of scientific thought follows in natural sequence on the great revolutions at earlier epochs in the history of science. Einstein’s special theory of relativity, which explains the indeterminateness of the frame of space and time, crowns the work of Copernicus who first led us to give up our insistence on a geocentric outlook on nature; Einstein's general theory of relativity, which reveals the curvature or non-Euclidean geometry of space and time, carries forward the rudimentary thought of those earlier astronomers who first contemplated the possibility that their existence lay on something which was not flat. These earlier revolutions are still a source of perplexity in childhood, which we soon outgrow; and a time will come when Einstein’s amazing revelations have likewise sunk into the commonplaces of educated thought.

[In childhood, to overcome fear, the] need took me back again and again to a sycamore tree rising from the earth at the edge of a ravine. It was a big, old tree that had grown out over the ravine, so that when you climbed it, you looked straight down fifty feet or more. Every time I climbed that tree, I forced myself to climb to the last possible safe limb and then look down. Every time I did it, I told myself I’d never do it again. But I kept going back because it scared me and I had to know I could overcome that.

A good scientist is a person in whom the childhood quality of perennial curiosity lingers on. Once he gets an answer, he has other questions.

As we were flying over the Mozambique Channel, which separates the island of Madagascar from the continent of Africa, we could clearly see the transverse sand bars at its bottom. It was just like a brook one waded in childhood.

Crowds of silent voices whisper in our ears, transforming the nature of what we see and hear. Some are those of childhood authorities and heroes; others come from family and peers. The strangest emerge from beyond the grave.

Curiosity atrophies after childhood unless it is transferred to an intellectual plane. The research worker is usually a person whose curiosity is turned toward seeking explanations for phenomena that are not understood.

Do you remember what Darwin says about music? He claims that the power of producing and appreciating it existed among the human race long before the power of speech was arrived at. Perhaps that is why we are so subtly influenced by it. There are vague memories in our souls of those misty centuries when the world was in its childhood.

Fractal geometry will make you see everything differently. There is a danger in reading further. You risk the loss of your childhood vision of clouds, forests, flowers, galaxies, leaves, feathers, rocks, mountains, torrents of water, carpet, bricks, and much else besides. Never again will your interpretation of these things be quite the same.

From earliest memory I wanted to be a surgeon, possibly influenced by the qualities of our family doctor who cared for our childhood ailments.

From my earliest childhood I nourished and cherished the desire to make a creditable journey in a new country, and write such a respectable account of its natural history as should give me a niche amongst the scientific explorers of the globe I inhabit, and hand my name down as a useful contributor of original matter.

From my father I learned to build things, to take them apart, and to fix mechanical and electrical equipment in general. I spent vast hours in a woodworking shop he maintained in the basement of our house, building gadgets, working both with my father and alone, often late into the night. … This play with building, fixing, and designing was my favorite activity throughout my childhood, and was a wonderful preparation for my later career as an experimentalist working on the frontiers of chemistry and physics.

Gradually, at various points in our childhoods, we discover different forms of conviction. There’s the rock-hard certainty of personal experience (“I put my finger in the fire and it hurt,”), which is probably the earliest kind we learn. Then there’s the logically convincing, which we probably come to first through maths, in the context of Pythagoras’s theorem or something similar, and which, if we first encounter it at exactly the right moment, bursts on our minds like sunrise with the whole universe playing a great chord of C Major.

I have from my childhood, in conformity with the precepts of a mother void of all imaginary fear, been in the constant habit of taking toads in my hand, and applying them to my nose and face as it may happen. My motive for doing this very frequently is to inculcate the opinion I have held, since I was told by my mother, that the toad is actually a harmless animal; and to whose manner of life man is certainly under some obligation as its food is chiefly those insects which devour his crops and annoy him in various ways.

If a man, holding a belief which he was taught in childhood or persuaded of afterwards, keeps down and pushes away any doubts which arise about it in his mind, purposely avoids the reading of books and the company of men that call in question or discuss it, and regards as impious those questions which cannot easily be asked without disturbing it—the life of that man is one long sin against mankind.

In Japan, an exceptional dexterity that comes from eating with chopsticks … is especially useful in micro-assembly. (This … brings smiles from my colleagues, but I stand by it. Much of modern assembly is fine tweezer work, and nothing prepares for it better than eating with chopsticks from early childhood.)

It has been my misfortune never to have had any neighbours whose studies have led them towards the pursuit of natural knowledge; so that, for want of a companion to quicken my industry and sharpen my attention, I have made but slender progress in a kind of information to which I have been attached from my childhood.

It is utterly false and cruelly arbitrary to put all the play and learning into childhood, all the work into middle age, and all the regrets into old age.

It seems to me it [hands-on experience] was more prevalent in a more primitive society, where you’re closer to machinery. [As a university teacher,] I see this with farm kids all the time. They have a more or less rugged self-reliance.

It seems very strange … that in the course of the world’s history so obvious an improvement should never have been adopted. … The next generation of Britishers would be the better for having had this extra hour of daylight in their childhood.

It’s never too late for a happy childhood.

Mathematics is like childhood diseases. The younger you get it, the better.

Memories of childhood are unreliable. I am lucky to have documentary evidence dating from the age of nine. The evidence is an unfinished novel, found among my mother's papers forty-three years later, with the title Sir Phillip Roberts’ Ero-Lunar Collision. Sir Phillip is a professional astronomer, evidently a role model for a young scientist. The style of the novel is copied from Jules Verne; the story was suggested by the near approach of the asteroid Eros in the year 1931. Here is a sample of the dialogue:
“Will Eros really go right through our Sattelite?” said Major Forbes.
“Yes,” said Sir Phillip, “its speed, and its small weight and resistance, will bring it through our Sattelite, it will be a picture, suddenly rising white-hot from the Moon’s internal fires, followed by a stream of liquid lava.”
So it was Jules Verne and Eros that turned my infant thoughts to science.

Most of us have had moments in childhood when we touched the divine presence. We did not think it extraordinary because it wasn’t; it was just a beautiful moment filled with love. In those simple moments our hearts were alive, and we saw the poignant beauty of life vividly with wonder and appreciation.

My whole life is devoted unreservedly to the service of my sex. The study and practice of medicine is in my thought but one means to a great end, for which my very soul yearns with intensest passionate emotion, of which I have dreamed day and night, from my earliest childhood, for which I would offer up my life with triumphant thanksgiving, if martyrdom could secure that glorious end:— the true ennoblement of woman, the full harmonious development of her unknown nature, and the consequent redemption of the whole human race.

Old age is but a second childhood.

Our truest systems of science had small beginnings, gradual and countless contributions, and finally took their place in use, as each of you, from helpless childhood and feeble boyhood, have grown to your present strength and maturity. No such system could be born in a day. It was not as when nature in fitful pulsations of her strength suddenly lifted the land into mountain ranges, but rather, as with small accretions, gathered in during countless years, she builds her islands in the seas.

Professor von Pirquet has come to this country exactly at the right time to aid us. He has shown us how to detect tuberculosis before it has become so developed as to be contagious and has so taken hold of the individual as to be recognized by any other means. In thousands of cases I for my part am unable to detect tuberculosis in infancy or early childhood without the aid of the tuberculin test which Prof. von Pirquet has shown to be the best. He has taught us how by tubercular skin tests, to detect it. ... What Dr. von Pirquet has done already will make his name go down to posterity as one of the great reformers in tuberculin tests and as one who has done an immense amount of good to humanity. The skin test in twenty-four hours will show you whether the case is tubercular.

Q: Which place has special childhood memories for you?
A: Charnwood Forest, Leicestershire.

Q: In which place do you feel most “at home”?
A: Richmond, Surrey, where I live near Richmond Hill.

Q: In which place have you felt ill at ease or uncomfortable?
A: The Democratic Republic of the Congo.
Q: Which place that you have visited has for you a “tingle factor?”
A: New Guinea.

Q: Which place that you have visited has given you most hope about the future?
A: A primary school.

Q: Which place would you like to revisit?
A: Tuscany.

Religion is comparable to a childhood neurosis.

Scientists have one thing in common with children: curiosity. To be a good scientist you must have kept this trait of childhood, and perhaps it is not easy to retain just one trait. A scientist has to be curious like a child; perhaps one can understand that there are other childish features he hasn't grown out of.

The childhood shows the man
As morning shows the day.

The choice of zoology as a main subject [at university] was to follow up my childhood love of nature. … My animal studies never became quite what I had hoped for. We hardly heard of wild beasts and the way they lived in the wilderness. We sliced up intestines and looked at them under the microscope … but their life and function in the environment was ignored in favor of their Latin names. … Was our knowledge of nature superior to, or only different from, that of the eagle-eyed Polynesian islanders, who specialized in appraising nature the way it could best benefit man? I had to think as a scientist now. Not as a Polynesian yet. Knowledge was to be sought independently of its purpose.

The earliest of my childhood recollections is being taken by my grandfather when he set out in the first warm days of early spring with a grubbing hoe (we called it a mattock) on his shoulder to seek the plants, the barks and roots from which the spring medicine for the household was prepared. If I could but remember all that went into that mysterious decoction and the exact method of preparation, and with judicious advertisement put the product upon the market, I would shortly be possessed of wealth which might be made to serve the useful purpose of increasing the salaries of all pathologists. … But, alas! I remember only that the basic ingredients were dogwood bark and sassafras root, and to these were added q.s. bloodroot, poke and yellow dock. That the medicine benefited my grandfather I have every reason to believe, for he was a hale, strong old man, firm in body and mind until the infection came against which even spring medicine was of no avail. That the medicine did me good I well know, for I can see before me even now the green on the south hillside of the old pasture, the sunlight in the strip of wood where the dogwood grew, the bright blossoms and the delicate pale green of the leaf of the sanguinaria, and the even lighter green of the tender buds of the sassafras in the hedgerow, and it is good to have such pictures deeply engraved in the memory.

The greatest scandal of the century in American psychiatry … is the growing mania among thousands of inept therapists, family counselors, and social workers for arousing false memories of childhood sexual abuse.

The progress of the individual mind is not only an illustration, but an indirect evidence of that of the general mind. The point of departure of the individual and of the race being the same, the phases of the mind of a man correspond to the epochs of the mind of the race. Now, each of us is aware, if he looks back upon his own history, that he was a theologian in his childhood, a metaphysician in his youth, and a natural philosopher in his manhood. All men who are up to their age can verify this for themselves.

The realization that our small planet is only one of many worlds gives mankind the perspective it needs to realize sooner that our own world belongs to all of its creatures, that the Moon landing marks the end of our childhood as a race and the beginning of a newer and better civilization.

The river Mersey, a mile-wide estuary not unlike the Hudson, perhaps in my childhood even more filthy. We used to say “the quality of Mersey is not strained.”

The young genius early exults in the contemplation of power and beauty. During Scott’s childhood, a frightful thunder-storm raged at Edinburgh, which made his brothers and the domestics huddle together in one room, shivering with fear at every peal. Young Walter was found lying on his back in the garden, the rain pitilessly pelting his face, while he, almost convulsed with delight, shouted, at every flash, “bonnie! bonnie!” Schiller was found by his father, on a similar occasion, perched upon a tree, and, on being harshly questioned as to his object, whimpered out that he wanted to see where the thunder came from.

This speaker reminds me of my childhood in Budapest. There were gypsy magicians who came to town to entertain us children. But as I recollect, there was one important difference: the gypsy only seemed to violate the laws of nature, he never really violated them!

Today the world changes so quickly that in growing up we take leave not just of youth but of the world we were young in. … Fear and resentment of what is new is really a lament for the memories of our childhood.

When even the brightest mind in our world has been trained up from childhood in a superstition of any kind, it will never be possible for that mind, in its maturity, to examine sincerely, dispassionately, and conscientiously any evidence or any circumstance which shall seem to cast a doubt upon the validity of that superstition. I doubt if I could do it myself.

When I first ventured into the Gulf of Mexico in the 1950s, the sea appeared to be a blue infinity too large, too wild to be harmed by anything that people could do. I explored powder white beaches, dense marshes, mangrove forests, and miles of sea grass meadows alive with pink sea urchins, tiny shrimps, and seahorses half the size of my little finger. … Then, in mere decades, not millennia, the blue wilderness of my childhood disappeared: biologic change in the space of a lifetime.