This page contains a collection of philosophical quotes on knowledge, arranged in roughly chronological order. These quotes are all genuine and details about the author, book, chapter number, and translation are included where applicable. Quotes that begin with a section of bold text are my personal favourites. Without further ado, here are nineteen philosophical quotes on knowledge:
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 seeing (one might say) to everything else. The reason is that this, most of all the senses, makes us know and brings to light many differences between things.
– Aristotle, Metaphysics, 980a1, trans. W. D. Ross
It is absurd to seek at the same time knowledge and the way of attaining knowledge; and it is not easy to get even one of the two.
– Aristotle, Metaphysics, 995a13, trans. W. D. Ross
It is one thing, however, to remember, another to know. To remember is to safeguard something entrusted to your memory, whereas to know, by contrast, is actually to make each item your own, and not to be dependent on some original and be constantly looking to see what the master said.
– Seneca, Letters from a Stoic, 33, trans. Robin Campbell
Knowledge, if it does not determine action, is dead to us.
– Plotinus, First Ennead, II, 4, trans. MacKenna & Page
Knowledge is loved, not that any good may come to it but that it may be possessed.
– St Thomas Aquinas, Summa Theologica, I, 60, 3, trans. Fathers of the English Dominican Province
In truth, knowledge is a great and very useful quality; those who despise it give evidence enough of their stupidity. But yet I do not set its value at that extreme measure that some attribute to it, like Herillus the philosopher, who placed in it the sovereign good, and held that it was in its power to make us wise and content. That I do not believe, nor what others have said, that knowledge is the mother of all virtue, and that all vice is produced by ignorance. If that is true, it is subject to a long interpretation.
– Michel de Montaigne, Essays, II, 12, Apology for Raymond Sebond, trans. Donald Frame
Some years ago I was struck by how many false things I had believed, and by how doubtful was the structure of beliefs that I had based on them. I realized that if I wanted to establish anything in the sciences that was stable and likely to last, I needed – just once in my life – to demolish everything completely and start again from the foundations.
– René Descartes, Meditations on First Philosophy, I, trans. Elizabeth S. Haldane.
Since we cannot be universal and know all that is to be known of everything, we ought to know a little about everything. For it is far better to know something about everything than to know all about one thing. This universality is the best. If we can have both, still better; but if we must choose, we ought to choose the former. And the world feels this and does so; for the world is often a good judge.
– Blaise Pascal, Pensées, I, 37, trans. W. F. Trotter
Our intellect holds the same position in the world of thought as our body occupies in the expanse of nature.
Limited as we are in every way, this state which holds the mean between two extremes is present in all our impotence. Our senses perceive no extreme. Too much sound deafens us; too much light dazzles us; too great distance or proximity hinders our view. Too great length and too great brevity of discourse tend to obscurity; too much truth is paralysing (I know some who cannot understand that to take four from nothing leaves nothing). First principles are too self-evident for us; too much pleasure disagrees with us. Too many concords are annoying in music; too many benefits irritate us; we wish to have the wherewithal to over-pay our debts. . . . We feel neither extreme heat nor extreme cold. Excessive qualities are prejudicial to us and not perceptible by the senses; we do not feel but suffer them. Extreme youth and extreme age hinder the mind, as also too much and too little education. In short, extremes are for us as though they were not, and we are not within their notice. They escape us, or we them.
This is our true state; this is what makes us incapable of certain knowledge and of absolute ignorance. We sail within a vast sphere, ever drifting in uncertainty, driven from end to end. When we think to attach ourselves to any point and to fasten to it, it wavers and leaves us; and if we follow it, it eludes our grasp, slips past us, and vanishes for ever. Nothing stays for us. This is our natural condition, and yet most contrary to our inclination; we burn with desire to find solid ground and an ultimate sure foundation whereon to build a tower reaching to the Infinite. But our whole groundwork cracks, and the earth opens to abysses.
Let us therefore not look for certainty and stability. Our reason is always deceived by fickle shadows; nothing can fix the finite between the two Infinites, which both enclose and fly from it.
If this be well understood, I think that we shall remain at rest, each in the state wherein nature has placed him. As this sphere which has fallen to us as our lot is always distant from either extreme, what matters it that man should have a little more knowledge of the universe? If he has it, he but gets a little higher. Is he not always infinitely removed from the end, and is not the duration of our life equally removed from eternity, even if it lasts ten years longer?
In comparison with these Infinites all finites are equal, and I see no reason for fixing our imagination on one more than on another. The only comparison which we make of ourselves to the finite is painful to us.
– Blaise Pascal, Pensées, II, 72, trans. W. F. Trotter
Let us then suppose the mind to be, as we say, white paper, void of all characters, without any ideas:— How comes it to be furnished? Whence comes it by that vast store which the busy and boundless fancy of man has painted on it with an almost endless variety? Whence has it all the materials of reason and knowledge? To this I answer, in one word, from Experience. In that all our knowledge is founded; and from that it ultimately derives itself.
– John Locke, An Essay Concerning Human Understanding, Bk. 2, Ch. 1, 1, 2
The sweetest and most inoffensive path of life leads through the avenues of science and learning; and whoever can either remove any obstructions in this way, or open up any new prospect, ought so far to be esteemed a benefactor to mankind. And though these researches may appear painful and fatiguing, it is with some minds as with some bodies, which being endowed with vigorous and florid health, require severe exercise, and reap a pleasure from what, to the generality of mankind, may seem burdensome and laborious. Obscurity, indeed, is painful to the mind as well as to the eye; but to bring light from obscurity, by whatever labour, must needs be delightful and rejoicing.
– David Hume, An Enquiry Concerning Human Understanding, I, 6
Whatever moralists may hold, the human understanding is greatly indebted to the passions, which, it is universally allowed, are also much indebted to the understanding. It is by the activity of the passions that our reason is improved; for we desire knowledge only because we wish to enjoy; and it is impossible to conceive any reason why a person who has neither fears nor desires should give himself the trouble of reasoning.
– Jean-Jacques Rousseau, Discourse on the Origin of Inequality, I, trans. G. D. H. Cole
Knowledge always desires increase: it is like fire, which must be first kindled by some external agent, but which will afterwards propagate itself.
– Samuel Johnson, Letter to William Drummond (Aug. 13, 1766)
A desire of knowledge is the natural feeling of mankind; and every human being, whose mind is not debauched, will be willing to give all that he has to get knowledge.
– Samuel Johnson as quoted in Boswell, The Life of Samuel Johnson (July 30, 1763)
Theoretical knowledge may be defined as knowledge of what is, practical knowledge as the representation of what ought to be.
– Immanuel Kant, Critique of Pure Reason, A 633/B 611 trans. N. Kemp Smith
Henceforth, my dear philosophers, let us be on guard against the dangerous old conceptual fiction that posited a “pure, will-less, painless, timeless knowing subject” let us guard against the snares of such contradictory concepts as “pure reason,” “absolute spirituality,” “knowledge in itself”: these always demand that we should think of an eye that is completely unthinkable, an eye turned in no particular direction, in which the active and interpreting forces, through which alone seeing becomes seeing something, are supposed to be lacking; these always demand of the eye an absurdity and a nonsense. There is only a perspective seeing, only a perspective “knowing” and the more affects we allow to speak about one thing, the more eyes, different eyes, we can use to observe one thing, the more complete will our “concept” of this thing, our “objectivity,” be.
– Friedrich Nietzsche, On The Genealogy of Morals, III, 12, trans. Kaufmann and Hollingdale
Better to know nothing than to half know many things!
– Friedrich Nietzsche, Thus Spoke Zarathustra, IV, 64, trans. R. J. Hollingdale
It is clear that knowledge is a sub-class of true beliefs: every case of knowledge is a case of true belief, but not vice versa. It is very easy to give examples of true beliefs that are not knowledge. There is the man who looks at a clock which is not going, though he thinks it is, and who happens to look at it at the moment when it is right; this man acquires a true belief as to the time of day, but cannot be said to have knowledge. There is the man who believes, truly, that the last name of the Prime Minister in 1906 began with a B, but who believes this because he thinks that Balfour was Prime Minister then, whereas in fact it was Campbell Bannerman. There is the lucky optimist who, having bought a ticket for a lottery, has an unshakeable conviction that he will win, and, being lucky, does win. Such instances can be multiplied indefinitely, and show that you cannot claim to have known merely because you turned out to be right.
What character in addition to truth must a belief have in order to count as knowledge? The plain man would say there must be sound evidence to support the belief. As a matter of common sense this is right in most of the cases in which doubt arises in practice, but . . . there are various unsatisfactory features in this traditional doctrine, though I am not at all sure that, in the end, we can substitute anything very much better.
– Bertrand Russell, Human Knowledge, II, 11
It is difficult to define knowledge, difficult to decide whether we have any knowledge, and difficult, even if it is conceded that we sometimes have knowledge, to discover whether we can ever know that we have knowledge in this or that particular case.
– Bertrand Russell, The Analysis of Mind, XIII
Know of a quote that I’ve missed? Let me know in the comments below!