This heart within me I can feel, and I judge that it exists. This world I can touch, and I likewise judge that it exists. There ends all my knowledge, and the rest is construction. For if I try to seize this self of which I feel sure, if I try to define and to summarize it, it is nothing but water slipping through my fingers. I can sketch one by one all the aspects it is able to assume, all those likewise that have been attributed to it, this upbringing, this origin, this ardor or these silences, this nobility or this vileness. But aspects cannot be added up. This very heart which is mine will forever remain indefinable to me. Between the certainty I have of my existence and the content I try to give to that assurance, the gap will never be filled. Forever I shall be a stranger to myself.

If you reject absolutely any single sensation without stopping to discriminate with respect to that which awaits confirmation between matter of opinion and that which is already present, whether in sensation or in feelings or in any immediate perception of the mind, you will throw into confusion even the rest of your sensations by your groundless belief and so you will be rejecting the standard of truth altogether. If in your ideas based upon opinion you hastily affirm as true all that awaits confirmation as well as that which does not, you will not escape error, as you will be maintaining complete ambiguity whenever it is a case of judging between right and wrong opinion.

Sincerity is the end and beginning of things; without sincerity there would be nothing. On this account, the superior man regards the attainment of sincerity as the most excellent thing.

Some say that the body is the "tomb" of the soul, their notion being that the soul is buried in the present life; and again, because by its means the soul gives any signs which it gives, it is for this reason also properly called "sign". But I think it most likely that the Orphic poets gave this name, with the idea that the soul is undergoing punishment for something; they think it has the body as an enclosure to keep it safe, like a prison, and this is, as the name itself denotes, the "safe" for the soul, until the penalty is paid, and not even a letter needs to be changed.

Every plant, which my heavenly Father hath not planted, shall be rooted up. Let them alone: they be blind leaders of the blind. And if the blind lead the blind, both shall fall into the ditch. 15:13-14 (KJV)

All men by nature desire to know. An indication of this is the delight we take in our senses; for even apart from their usefulness they are loved for themselves; and above all others the sense of sight. For not only with a view to action, but even when we are not going to do anything, we prefer sight to almost everything else. The reason is that this, most of all the senses, makes us know and brings to light many differences between things.

Men all say, "We are wise"; but being driven forward and taken in a net, a trap, or a pitfall, they know not how to escape. Men all say, "We are wise"; but happening to choose the course of the Mean, they are not able to keep it for a round month.

So watch yourselves. If your brother sins, rebuke him, and if he repents, forgive him. If he sins against you seven times in a day, and seven times comes back to you and says, 'I repent,' forgive him. (Luke 17:3-4) (NIV)

Life continues, and some mornings, weary of the noise, discouraged by the prospect of the interminable work to keep after, sickened also by the madness of the world that leaps at you from the newspaper, finally convinced that I will not be equal to it and that I will disappoint everyone, all I want to do is sit down and wait for evening. This is what I feel like, and sometimes I yield to it.

No matter how various the subject matter I write on, I was a science-fiction writer first and it is as a science-fiction writer that I want to be identified.

Now any dogma, based primarily on faith and emotionalism, is a dangerous weapon to use on others, since it is almost impossible to guarantee that the weapon will never be turned on the user.

Of our desires some are natural and necessary, others are natural but not necessary; and others are neither natural nor necessary, but are due to groundless opinion.

Why dost thou not retire like a guest sated with the banquet of life, and with calm mind embrace, thou fool, a rest that knows no care?

It is the way of the superior man to prefer the concealment of his virtue, while it daily becomes more illustrious, and it is the way of the mean man to seek notoriety, while he daily goes more and more to ruin. It is characteristic of the superior man, appearing insipid, yet never to produce satiety; while showing a simple negligence, yet to have his accomplishments recognized; while seemingly plain, yet to be discriminating. He knows how what is distant lies in what is near. He knows where the wind proceeds from. He knows how what is minute becomes manifested. Such a one, we may be sure, will enter into virtue.

One could construe the life of man as a great discourse in which the various people represent different parts of speech (the same might apply to states). How many people are just adjectives, interjections, conjunctions, adverbs? How few are substantives, active verbs, how many are copulas? Human relations are like the irregular verbs in a number of languages where nearly all verbs are irregular.

Even before the bomb, one did not breathe too easily in this tortured world. Now we are given a new source of anguish; it has all the promise of being our greatest anguish ever. There can be no doubt that humanity is being offered its last chance. Perhaps this is an occasion for the newspapers to print a special edition. More likely, it should be cause for a certain amount of reflection and a great deal of silence.

The principles of pleasure are not firm and stable. They are different in all mankind, and variable in every particular with such a diversity that there is no man more different from another than from himself at different times.

If we are not stupid or insincere when we say that the good or ill of man lies within his own will, and that all beside is nothing to us, why are we still troubled?

Man is a goal-seeking animal. His life only has meaning if he is reaching out and striving for goals.

It is the act of an ill-instructed man to blame others for his own bad condition; it is the act of one who has begun to be instructed, to lay the blame on himself; and of one whose instruction is completed, neither to blame another, nor himself.

If you well apprehend and keep in mind these things, nature free at once and rid of her haughty lords is seen to do all things spontaneously of herself without the meddling of the gods.

Verily I say unto you, If ye have faith, and doubt not, ye shall not only do this which is done to the fig tree, but also if ye shall say unto this mountain, Be thou removed, and be thou cast into the sea; it shall be done.

By such reflections and by the continuance in them of a divine nature, the qualities which we have described grew and increased among them; but when the divine portion began to fade away, and became diluted too often and too much with the mortal admixture, and the human nature got the upper hand, they then, being unable to bear their fortune, behaved unseemly, and to him who had an eye to see grew visibly debased, for they were losing the fairest of their precious gifts; but to those who had no eye to see the true happiness, they appeared glorious and blessed at the very time when they were full of avarice and unrighteous power.

The preceding merely defines a way of thinking. But the point is to live.

If you're going to write a story, avoid contemporary references. They date a story and they have no staying power.

A robot may not injure a human being, or, through inaction, allow a human being to come to harm.

Of all the books I have ever worked on, I think Asimov's Guide to Shakespeare gave me the most pleasure, day in, day out. For months and months I lived and thought Shakespeare, and I don't see how there can be any greater pleasure in the world, any pleasure, that is, that one can indulge in for as much as ten hours without pause, day after day indefinitely.

My kingdom is not of this world: if my kingdom were of this world, then would my servants fight, that I should not be delivered to the Jews: but now is my kingdom not from hence. 18: 36, (KJV)

The world is divided into men who have wit and no religion and men who have religion and no wit.

I am a Roman citizen.

Show me someone who is ill and yet happy, in danger and yet happy, dying and yet happy, exiled and yet happy. Show me such a person; by the gods, how greatly I long to see a Stoic!

That which distinguishes the Christian narrow way from the common human narrow way is the voluntary. Christ was not someone who coveted earthly things but had to be satisfied with poverty, no, he chose poverty.

The fact that the general incidence of leukemia has doubled in the last two decades may be due, partly, to the increasing use of x-rays for numerous purposes. The incidence of leukemia in doctors, who are likely to be so exposed, is twice that of the general public. In radiologists the incidence is ten times greater.

Go into the city to such a man, and say unto him, The Master saith, My time is at hand; I will keep the passover at thy house with my disciples. 26:18 (KJV)

I think that the task of philosophy is not to provide answers, but to show how the way we perceive a problem can be itself part of a problem.

A man is more a man through the things he keeps to himself than through those he says.

The person who is going to preach ought to live in the Christian thoughts and ideas: they ought to be his daily life. If so, this is the view of Christianity, then you, too, will have eloquence enough and precisely that which is needed when you speak extemporaneously without specific preparation. However, it is fallacious eloquence if someone, without otherwise occupying himself with, without living in these thoughts, once in a while sits down and laboriously collects such thoughts, perhaps in the field of literature, and then works them into a well-composed discourse, which is then committed to memory and delivered superbly, with respect both to voice and diction and gestures.

To wisdom belongs the intellectual apprehension of things eternal; to knowledge, the rational apprehension of things temporal.

Blessed is the lion which becomes man when consumed by man; and cursed is the man whom the lion consumes, and the lion becomes man. (7) This saying has been interpreted by some as referring to such anger as consumes a man…(rather than is consumed by him, through his reason and love), 'til that man is the lion of Anger. Other more mystical interpretations might also be found or devised that have merit.

After logic we must proceed to philosophy proper. Here too we have to learn from our predecessors, just as in mathematics and law. Thus it is wrong to forbid the study of ancient philosophy. Harm from it is accidental, like harm from taking medicine, drinking water, or studying law.

Incomprehensible and immutable is the love wherewith God loves. He did not begin to love us only on the day we were reconciled to Him by the blood of His Son; He loved us before the world was made, that we too might become His sons together with His Only-begotten Son, long before we had any existence.

All things are nourished together without their injuring one another. The courses of the seasons, and of the sun and moon, are pursued without any collision among them. The smaller energies are like river currents; the greater energies are seen in mighty transformations. It is this which makes heaven and earth so great.

Philosophers do not claim that God does not know particulars; they rather claim that He does not know them the way humans do. God knows particulars as their Creator whereas humans know them as a privileged creations of God might know them.

The institutions of the Ruler are rooted in his own character and conduct, and sufficient attestation of them is given by the masses of the people. He examines them by comparison with those of the three kings, and finds them without mistake. He sets them up before Heaven and Earth, and finds nothing in them contrary to their mode of operation. He presents himself with them before spiritual beings, and no doubts about them arise. He is prepared to wait for the rise of a sage a hundred ages after, and has no misgivings. His presenting himself with his institutions before spiritual beings, without any doubts arising about them, shows that he knows Heaven. His being prepared, without any misgivings, to wait for the rise of a sage a hundred ages after, shows that he knows men.

Science is a systematic method for studying and working out those generalizations that seem to describe the behavior of the universe. It could exist as a purely intellectual game that would never affect the practical life of human beings either for good or evil, and that was very nearly the case in ancient Greece, for instance. Technology is the application of scientific findings to the tools of everyday life, and that application can be wise or unwise, useful or harmful. Very often, those who govern technological decisions are not scientists and know little about science.

Yea; have ye never read, Out of the mouth of babes and sucklings thou hast perfected praise? 21:16 (KJV)

It is not among extraordinary and fantastic things that excellence is to be found, of whatever kind it may be. We rise to attain it and become removed from it: it is oftenest necessary to stoop for it.

The flesh receives as unlimited the limits of pleasure; and to provide it requires unlimited time. But the mind, intellectually grasping what the end and limit of the flesh is, and banishing the terrors of the future, procures a complete and perfect life, and we have no longer any need of unlimited time. Nevertheless the mind does not shun pleasure, and even when circumstances make death imminent, the mind does not lack enjoyment of the best life.