[after quoting from Lucretius] In the face of warfare and inevitable death, there is no wisdom but in ataraxia, "to look on all things with a mind at peace"." Here, clearly, the old pagan joy of life is gone, and an almost exotic spirit touches a broken lyre. History, which is nothing if not humorous, was never so facetious as when she gave to this abstemious and epic pessimist the name of Epicurean.

She is a woman now, and not an idle girl, not a domestic ornament or a sexual convenience anymore.

Rooted in freedom, bonded in the fellowship of danger, sharing everywhere a common human blood, we declare again that all men are brothers, and that mutual tolerance is the price of liberty.

Philosophy accepts the hard and hazardous task of dealing with problems not yet open to the methods of science - problems like good and evil, beauty and ugliness, order and freedom, life and death; so soon as a field of inquiry yields knowledge susceptible of exact formulation it is called science. Every science begins as philosophy and ends as art; it arises in hypothesis and flows into achievement.

It is life that educates, and perhaps love more than anything else in life.

British rule in India is the most sordid and criminal exploitation of one nation by another in all recorded history. I propose to show that England has year by year been bleeding India to the point of death, and that self-government of India by the Hindus could not within any reasonable probability, have worse results than the present form of alien domination.

To speak ill of others is a dishonest way of praising ourselves; let us be above such transparent egotism. If you can't say good and encouraging things, say nothing. Nothing is often a good thing to do, and always a clever thing to say.

Life is that which is discontent, which struggles and seeks, which suffers and creates.

Nothing in all literature is so depressing as the "Dissertations" of the slave [Epictetus], unless it be the "Meditations" of the Emperor [Marcus Aurelius] ...[after some excerpts from the two books]..... In such passages we feel the proximity of Christianity and its dauntless martyrs; indeed were not the Christian ethic of self-denial, the Christian political ideal of an almost communistic brotherhood of man, and the Christian eschatology of the final conflagration of all the world, fragments of Stoic doctrine floating on the stream of thought? In Epictetus the Greco-Roman soul has lost its paganism, and is ready for a new faith".

A man is as old as his arteries, and as young as his ideas.

All the problems that disturb us today-the cutting down of forests and the erosion of the soil; the emancipation of woman and the limitation of the family; the conservatism of the established, and the experimentalism of the unplaced, in morals, music, and government; the corruptions of politics and the perversions of conduct; the conflict of religion and science, and the weakening of the supernatural supports of morality; the war of the classes, the nations, and the continents; the revolutions of the poor against the economically powerful rich, and of the rich against the politically powerful poor; the struggle between democracy and dictatorship, between individualism and communism, between the East and the West-all these agitated, as if for our instruction, the brilliant and turbulent life of ancient Hellas. There is nothing in Greek civilization that does not illuminate our own.

Philosophy is a hypothetical interpretation of the unknown (as in metaphysics), or of the inexactly known (as in ethics or political philosophy); it is the front trench in the siege of truth.

The principle of the family was mutual aid; but the principle of society is competition, the struggle for existence, the elimination of the weak and the survival of the strong.

This, evidently was not a minor civilization, produced by inferior people. It ranks with the highest civilizations of history, and some, like Keyserling, would place it at the head and summit of all. The British conquest of India was the invasion and destruction of a high civilization by a trading company utterly without scruple or principle, careless of art, greedy of gain, overrunning with fire and sword a country temporarily disordered and helpless, bribing and murdering, annexing and stealing, and beginning that career of illegal and "legal" plunder which has now gone on ruthlessly for one hundred and seventy-three years, and goes on at this moment while in our secure comfort we write and read. Those who have seen the unspeakable poverty and physiological weakness of the Hindus today will hardly believe that it was the wealth of eighteenth century India which attracted the commercial pirates of England and France.

Civilization exists by geological consent, subject to change without notice.

Childhood may be defined as the age of play; therefore some children are never young, and some adults are never old.

Both Stoicism and Epicureanism - the apathetic acceptance of defeat, and the effort to forget defeat in the arms of pleasure - were theories as to how one might yet be happy though subjugated or enslaved; precisely as the stoicism of Schopenhauer and the despondent epicureanism of Renan were in the nineteenth century the symbols of a shattered revolution and a broken France.

Here and everywhere is the struggle for existence, life inextricably enmeshed with war. All life living at the expense of life, every organism eating other organisms forever.

There is no greater drama in human record than the sight of a few Christians, scorned or oppressed by a succession of emperors, bearing all trials with a fierce tenacity, multiplying quietly, building order while their enemies generated chaos, fighting the sword with the word, brutality with hope, and at last defeating the strongest state that history has known. Caesar and Christ had met in the arena, and Christ had won.

Those who try to include all life when trying to determine justice: Should a man be executed for killing a fly? No? The fly has a short life span? The fly is small? All these rationalizations can be applied to you, by a creature that lives longer, is bigger, etc. #philosophy 

By now it may be clear that the position I'm developing is a sort of post-Darwinian Kantianism.

Scientific revolutions are inaugurated by a growing sense... that an existing paradigm has ceased to function adequately in the exploration of an aspect of nature to which that paradigm itself had previously led the way. p. 91

The subject of a gestalt demonstration knows that his perception has shifted because he can make it shift back and forth repeatedly while he holds the same book or piece of paper in his hands. Aware that nothing in his environment has changed, he directs his attention increasingly not to the figure (duck or rabbit) but to the lines of the paper he is looking at. Ultimately he may even learn to see those lines without seeing either of the figures, and he may then say (what he could not legitimately have said earlier) that it is these lines that he really sees but that he sees them alternately as a duck and as a rabbit. ...As in all similar psychological experiments, the effectiveness of the demonstration depends upon its being analyzable in this way. Unless there were an external standard with respect to which a switch of vision could be demonstrated, no conclusion about alternate perceptual possibilities could be drawn. 

These examples point to the third and most fundamental aspect of the incommensurability of competing paradigms. In a sense that I am unable to explicate further, the proponents of competing paradigms practice their trades in different worlds. One contains constrained bodies that fall slowly, the other pendulums that repeat their motions again and again. In one, solutions are compounds, in the other mixtures. One is embedded in a flat, the other in a curved, matrix of space. Practicing in different worlds, the two groups of scientists see different things when they look from the same point in the same direction. Again, that is not to say that they can see anything they please. Both are looking at the world, and what they look at has not changed. But in some areas they see different things, and they see them in different relations one to the other. That is why a law that cannot even be demonstrated to one group of scientists may occasionally seem intuitively obvious to another. p. 149

We may, to be more precise, have to relinquish the notion, explicit or implicit, that changes of paradigm carry scientists and those who learn from them closer and closer to the truth.

Few people who are not actually practitioners of a mature science realize how much mop-up work of this sort a paradigm leaves to be done or quite how fascinating such work can prove in the execution.

History, if viewed as a repository for more than anecdote or chronology, could produce a decisive transformation in the image of science by which we are now possessed.

In the development of any science, the first received paradigm is usually felt to account quite successfully for most of the observations and experiments easily accessible to that science's practitioners. Further development, therefore, ordinarily calls for the construction of elaborate equipment, the development of an esoteric vocabulary and skills, and a refinement of concepts that increasingly lessens their resemblance to their usual common-sense prototypes. That professionalization leads, on the one hand, to an immense restriction of the scientist's vision and to a considerable resistance to paradigm change. The science has become increasingly rigid. On the other hand, within those areas to which the paradigm directs the attention of the group, normal science leads to a detail of information and to a precision of the observation-theory match that could be achieved in no other way.

These three classes of problems-determination of significant fact, matching of facts with theory, and articulation of theory-exhaust, I think, the literature of normal science, both empirical and theoretical. They do not, of course, quite exhaust the entire literature of science. There are also extraordinary problems, and it may well be their resolution that makes the scientific enterprise as a whole so particularly worthwhile. But extraordinary problems are not to be had for the asking. They emerge only on special occasions prepared by the advance of normal research.

Out-of-date theories are not in principle unscientific because they have been discarded. That choice, however, makes it difficult to see scientific development as a process of accretion.

Philosophers of science have repeatedly demonstrated that more than one theoretical construction can always be placed upon a given collection of data. History of science indicates that, particularly in the early developmental stages of a new paradigm, it is not even very difficult to invent such alternates. But that invention of alternates is just what scientists seldom undertake except during the pre-paradigm stage of their science's development and at very special occasions during its subsequent evolution. So long as the tools a paradigm supplies continue to prove capable of solving the problems it defines, science moves fastest and penetrates most deeply through confident employment of those tools. The reason is clear. As in manufacture so in science-retooling is an extravagance to be reserved for the occasion that demands it. The significance of crises is the indication they provide that an occasion for retooling has arrived.

The scientific enterprise as a whole does from time to time prove useful, open up new territory, display order, and test long-accepted belief. Nevertheless, the individual engaged on a normal research problem is almost never doing any one of these things. Once engaged, his motivation is of a rather different sort. What then challenges him is the conviction that, if only he is skillful enough, he will succeed in solving a puzzle that no one before has solved or solved so well.

Normal science, the activity in which most scientists inevitably spend almost all their time, is predicated on the assumption that the scientific community knows what the world is like. Normal science often suppresses fundamental novelties because they are necessarily subversive of its basic commitments.

Only when they must choose between competing theories do scientists behave like philosophers.

Scientists work from models acquired through education and through subsequent exposure to the literature often without quite knowing or needing to know what characteristics have given these models the status of community paradigms.

"Normal science" means research firmly based upon one or more past scientific achievements, achievements that some particular scientific community acknowledges for a time as supplying the foundation for its further practice.

I suggest that scientific knowledge, though logically more articulate and far more complex, is of this sort. The books and teachers from whom it is acquired present concrete examples together with a multitude of theoretical generalizations. Both are essential carriers of knowledge, and it is therefore Pickwickian to seek a methodological criterion that supposes the scientist can specify in advance whether each imaginable instance fits or would falsify his theory.

Normal science, the puzzle-solving activity we have just examined, is a highly cumulative enterprise, eminently successful in its aim, the steady extension of the scope and precision of scientific knowledge. In all these respects it fits with great precision the most usual image of scientific work. Yet one standard product of the scientific enterprise is missing. Normal science does not aim at novelties of fact or theory and, when successful, finds none.

Men whose research is based on shared paradigms are committed to the same rules and standards for scientific practice. That commitment and the apparent consensus it produces are prerequisites for normal science, i.e., for the genesis and continuation of a particular research tradition.

To my complete surprise, that exposure to out-of-date scientific theory and practice radically undermined some of my basic conceptions about the nature of science and the reasons for its special success.Those conceptions were ones I had previously drawn partly from scientific training itself and partly from a long-standing avocational interest in the philosophy of science. Somehow, whatever their pedagogic utility and their abstract plausibility, those notions did not at all fit the enterprise that historical study displayed. Yet they were and are fundamental to many discussions of science, and their failures of verisimilitude therefore seemed thoroughly worth pursuing. The result was a drastic shift in my career plans, a shift from physics to history of science and then, gradually, from relatively straightforward historical problems back to the more philosophical concerns that had initially led me to history.

We must now ask how changes of this sort can come about, considering first discoveries, or novelties of fact, and then inventions, or novelties of theory. That distinction between discovery and invention or between fact and theory will, however, immediately prove to be exceedingly artificial.

Ever since prehistoric antiquity one field of study after another has crossed the divide between what the historian might call its prehistory as a science and its history proper. These transitions to maturity have seldom been so sudden or so unequivocal as my necessarily schematic discussion may have implied. But neither have they been historically gradual, coextensive, that is to say, with the entire development of the fields within which they occurred.

Somehow, the practice of astronomy, physics, chemistry or biology normally fails to evoke the controversies over fundamentals that today seem endemic among, say, psychologists or sociologists. Attempting to discover the source of that difference led me to recognize the role in scientific research of what I have since called "paradigms." These I take to be universally recognized scientific achievements that for a time provide model problems and solutions for a community of practitioners.

In science, as in the playing card experiment, novelty emerges only with difficulty, manifested by resistance, against a background provided by expectation.

Alas! such is the miseducation of these days, it is only among those that are called the uneducated classes - those educated by experience - that you can look for a Man. Even among these, such a sight is growing daily rarer. My father, in several respects, has not, that I can think of, left his fellow. Perhaps among Scottish peasants what Samuel Johnson was among English authors. I have a sacred pride in my peasant father, and would not exchange him, even now, for any king known to me. Gold and the guinea stamp - the Man and the clothes of the man. Let me thank God for that greatest of blessings, and strive to live worthily of it.

If they be inhabited, what a scope for misery and folly; if they be un-inhabited, what a waste of space.

If you find many people who are hard and indifferent to you in a world that you consider to be unhospitable and cruel-as often, indeed, happens to a tender-hearted, stirring young creature-you will also find there are noble hearts who will look kindly on you, and their help will be precious to you beyond price.

Had there not been a natural goodness and indestructible force in my father, I see not how be could have bodied himself forth from these mean impediments. I suppose good precepts were not wanting. There was the Bible to read. Old John Orr, the schoolmaster, used from time to time to lodge with them; be was religious and enthusiastic (though in practice irregular with drink). In my grandfather, also, there seems to have been a certain geniality; for instance, he and a neighbor, Thomas Hogg, read "Anson's Voyages;" also tho "Arabian Nights," for which latter my father, armed with zealous conviction, scrupled not to censure them openly. By one means and another, at an early age he had acquired principles, lights that not only flickered, but shone steadily to guide his way.

The habits of study acquired at Universities are of the highest importance in after-life. At the season when you are in young years the whole mind is, as it were, fluid, and is capable of forming itself into any shape that the owner of the mind pleases to order it to form itself into. The mind is in a fluid state, but it hardens up gradually to the consistency of rock or iron, and you cannot alter the habits of an old man, but as he has begun he will proceed and go on to the last.

The more I reflect on it, the more I must admire how completely nature had taught him; how completely he was devoted to his work, to the task of his life, and content to let all pass by unheeded that had not relation to this. It is a singular fact, for example, that though a man of such openness and clearness, he had never, I believe, read three pages of Burns's poems. Not even when all about him became noisy and enthusiastic, I the loudest, on that matter, did he feel it worth while to renew his investigation of it, or once turn his face towards it. The poetry he liked (he did not call it poetry) was truth, and the wisdom of reality. Burns, indeed, could have done nothing for him. As high a greatness hung over his world as over that of Burns - the ever-present greatness of the Infinite itself. Neither was he, like Burns, called to rebel against the world, but to labor patiently at his task there, uniting the possible with the necessary to bring out the real, wherein also lay an ideal.