The brain is not responsible for any of the sensations.. the correct view [is] that the seat and source of sensation is the region of the heart….the motions of pleasure and pain, and generally all sensation plainly have their source in the heart.

The male has more teeth than the female in mankind, and sheep, and goats, and swine. This has not been observed in other animals.

But voice is a certain sound of that which is animated; for nothing inanimate emits a voice; but they are said to emit a voice from similitude, as a pipe, and a lyre, and such other inanimate things, have extension, modulation, and dialect; for thus it appears, because voice, also, has these.

It is not necessary to ask whether soul and body are one, just as it is not necessary to ask whether the wax and its shape are one, nor generally whether the matter of each thing and that of which it is the matter are one. For even if one and being are spoken of in several ways, what is properly so spoken of is the actuality.

Sound is the motion of that which is able to be moved, after the manner in which those things are moved, that rebound from smooth bodies, when any one strikes them. Not every thing... sounds... but it is necessary, that the body which is struck should be equable, that the air may collectively rebound, and be shaken. The differences, however, of bodies which sound, are manifested in the sound, which is in energy; for, as colours are not perceived without light, so neither are the sharp and the flat perceived without sound. But these things are asserted metaphorically, from those which pertain to the touch; for the sharp moves the sense much in a short time, but the flat a little in a long time. The sharp, therefore, is not rapid, and the flat slow; but such a motion is produced of the one, on account of celerity, and of the other on account of slowness, that, also, which is perceived in the touch, appears to be analogous to the acute and obtuse, for the acute, as it were, stings; but the obtuse, as it were, impels: because the one moves in a short, but the other in a long time. Hence it happens that the one is swift but the other slow. Let it therefore be thus determined concerning sound.

That body is heavier than another which, in an equal bulk, moves downward quicker.

The least initial deviation from the truth is multiplied later a thousandfold.

The bodies of which the world is composed are solids, and therefore have three dimensions. Now, three is the most perfect number,—it is the first of numbers, for of one we do not speak as a number, of two we say both, but three is the first number of which we say all. Moreover, it has a beginning, a middle, and an end.

According to one mode... nature is thus denominated, viz. the first subject matter to every thing which contains in itself the principle of motion and mutation. But after another mode it is denominated form, which subsists according to definition: for as art is called that which subsists according to art, and that which is artificial; so likewise nature is both called that which is according to nature, and that which is natural. ...that which is composed from these is not nature, but consists from nature; as, for instance, man. And this is nature in a greater degree than matter: for every thing is then said to be, when it is form in energy... entelecheia, rather than when it is incapacity.

As man loses touch with his 'inner being', his instinctive depths, he finds himself trapped in the world of consciousness, that is to say, in the world of other people. Any poet knows this truth; when other people sicken him, he turns to hidden resources of power inside himself, and he knows then that other people don't matter a damn. He knows the 'secret life' inside him is the reality; other people are mere shadows in comparison. but the 'shadows' themselves cling to one another. 'Man is a political animal', said Aristotle, telling one of the greatest lies in human history. Man has more in common with the hills, or with the stars, than with other men.

There is only one way to avoid criticism: do nothing, say nothing and be nothing.

We live in deeds, not years; in thoughts not breaths; // In feelings, not in figures on a dial. // We should count time by heart throbs. He most lives // Who thinks most, feels the noblest, acts the best.

The aim of art is to represent not the outward appearance of things, but their inward significance.

We are what we repeatedly do. Excellence, then, is not an act, but a habit.

What is the essence of life? To serve others and to do good.

Happiness depends upon ourselves

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

It is the mark of an educated mind to be able to entertain a thought without accepting it.

Remember that time slurs over everything, let all deeds fade, blurs all writings and kills all memories. Except are only those which dig into the hearts of men by love.

The single harmony produced by all the heavenly bodies singing and dancing together springs from one source and ends by achieving one purpose, and has rightly bestowed the name not of "disordered" but of "ordered universe" upon the whole.

A friend is one soul abiding in two bodies.

Hope is the dream of a waking man.

Suffering becomes beautiful when anyone bears great calamities with cheerfulness, not through insensibility but through greatness of mind.

Those who can, do, those who cannot, teach.

Humour is the only test of gravity, and gravity of humour. For a subject which would not bear raillery is suspicious; and a jest which would not bear a serious examination is certainly false wit.

Thus to the plain man there may be no metaphor in Aristotle's "substance", Descartes' "machine of nature," Newtonian "force" and "attraction," Thomas Young's "kinetic energy" and Michelangelo's figure of Leda. Placed in their customary contexts these present nothing to him but the face of literal truth. To the initiated, however, who are aware of the "gross original" senses as well as the now literal senses , they may become metaphors. There are no metaphors per se....

In matter-theory, as in astronomy, the Church's commitment to Aristotle was in due course to prove an embarassment. In both branches of science his speculative distinction between terrestrial and celestial matter was insecure from the very beginning. His own most loyal commentator, ... had already dreamt of a theory unifying all things, and John Philoponos... had rejected the distinction between terrestrial and celestial matter outright. Nevertheless, it was still an axiom of almost a thousand years later.

The old Greek philosophy, which in Europe in the later middle ages was synonymous with the works of Aristotle, considered motion as a thing for which a cause must be found: a velocity required a force to produce and to maintain it. The great discovery of Galileo was that not velocity, but acceleration requires a force. This is the law of inertia of which the real content is: the natural phenomena are described by differential equations of the second order.

Justice is of two kinds, justice in distribution and justice in rectification. ... Aristotle thinks primarily of setting things straight, and denies that rectificatory justice contains an element of 'tit for tat'.

I do not agree with Plato, but if anything could make me do so, it would be Aristotle's arguments against him.

It appears to me that there can be no question, that Aristotle stands forth, not only as the greatest figure in antiquity, but as the greatest intellect that has ever appeared upon the face of this earth.

The first clear expression of the idea of an element occurs in the teachings of the Greek philosophers. ... Aristotle ... who summarized the theories of earlier thinkers, developed the view that all substances were made of a primary matter... On this, different forms could be impressed... so the idea of the transmutation of the elements arose. Aristotle's elements are really fundamental properties of matter.... hotness, coldness, moistness, and dryness. By combining these in pairs, he obtained what are called the four elements, fire, air, earth and water... a fifth, immaterial, one was added, which appears in later writings as the quintessence. This corresponds with the ether. The elements were supposed to settle out naturally into the earth (below), water (the oceans), air (the atmosphere), fire and ether (the sky and heavenly bodies).

He penetrated into the whole universe of things, and subjected its scattered wealth to intelligence; and to him the greater number of the philosophical sciences owe their origin and distinction.

I do believe for certain, that he [Aristotle] first procured, by the help of the senses, such experiments and observations as he could, to assure him as much as was possible of the conclusion, and that he afterwards sought out the means how to demonstrate it; for this is the usual course in demonstrative sciences. And the reason thereof is, because when the conclusion is true, by the help of the resolutive method, one may hit upon some proposition before demonstrated, or come to some principle known per se; but if the conclusion be false, a man may proceed in infinitum, and never meet with any truth already known.

It is pretty definitely settled, among men competent to form a judgment, that Aristotle was the best educated man that ever walked on the surface of this earth. He is still, as he was in Dante's time, the "master of those that know." It is, therefore, not without reason that we look to him, not only as the best exponent of ancient education, but as one of the worthiest guides and examples in education generally. That we may not lose the advantage of his example, it will be well, before we consider his educational theories, to cast a glance at his life, the process of his development, and his work.

Is the ordinary person incompetent? No judgment is more decisive for one's political philosophy. It was perhaps the single most important difference in judgment between Plato and Aristotle.

Tolerance and apathy are the last virtues of a dying society.

Liars ... when they speak the truth they are not believed.

The roots of education ... are bitter, but the fruit is sweet.

For the purposes of poetry a convincing impossibility is preferable to an unconvincing possibility.

After these matters we ought perhaps next to discuss pleasure. For it is thought to be most intimately connected with our human nature, which is the reason why in educating the young we steer them by the rudders of pleasure and pain; it is thought, too, that to enjoy the things we ought and to hate the things we ought has the greatest bearing on virtue of character. For these things extend right through life, with a weight and power of their own in respect both to virtue and to the happy life, since men choose what is pleasant and avoid what is painful; and such things, it will be thought, we should least of all omit to discuss, especially since they admit of much dispute.

The best friend is he that, when he wishes a person's good, wishes it for that person's own sake.

When people are friends, they have no need of justice, but when they are just, they need friendship in addition.

What it lies in our power to do, it lies in our power not to do.

Therefore only an utterly senseless person can fail to know that our characters are the result of our conduct.

In cases of this sort, let us say adultery, rightness and wrongness do not depend on committing it with the right woman at the right time and in the right manner, but the mere fact of committing such action at all is to do wrong.

The vices respectively fall short of or exceed what is right in both passions and actions, while virtue both finds and chooses that which is intermediate.

Again, it is possible to fail in many ways (for evil belongs to the class of the unlimited ... and good to that of the limited), while to succeed is possible only in one way (for which reason also one is easy and the other difficult—to miss the mark easy, to hit it difficult); for these reasons also, then, excess and defect are characteristic of vice, and the mean of virtue; For men are good in but one way, but bad in many.

It is well said, then, that it is by doing just acts that the just man is produced, and by doing temperate acts the temperate man; without doing these no one would have even a prospect of becoming good. But most people do not do these, but take refuge in theory and think they are being philosophers and will become good in this way, behaving somewhat like patients who listen attentively to their doctors, but do none of the things they are ordered to do.

.... In a word, acts of any kind produce habits or characters of the same kind. Hence we ought to make sure that our acts are of a certain kind; for the resulting character varies as they vary. It makes no small difference, therefore, whether a man be trained in his youth up in this way or that, but a great difference, or rather all the difference.