We are reluctant to believe that the world we see is not the whole world. Yet the history of knowledge is largely the history of such reluctance being overcome.

We are apt to think that our ideas are the spontaneous product of the mind working upon experience; but in truth our ideas are largely the inheritance of past thought, and the experience upon which they work is itself colored by inherited assumptions.

The truth is that we never know for certain about anything. The degree of assurance we feel about any proposition is not a measure of its truth, but a measure of our familiarity with the evidence bearing on it.

It is a test of true theories not only to account for but to predict phenomena. We ought to accept a theory if it predicts things which observation subsequently confirms, and if no rival theory is equally successful.

We are compelled to feel that the world presented to our senses is not the world as it really is, but only the world as it appears to beings constituted as we are. The thing in itself remains forever unknowable.

It is not what the man of science believes that distinguishes him, but how and why he believes it. His beliefs are tentative, not dogmatic; they are based on evidence, not on authority or intuition.

The universe is under no obligation to make sense to you. But stranger still is the fact that it does — partially, provisionally, and always at the cost of uprooting what we thought we already knew.

The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd; indeed in view of the silliness of the majority of mankind, a widespread belief is more likely to be foolish than sensible.

A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.

The mind is furnished with a set of instincts which seek out certain kinds of phenomena and ask for explanations of certain kinds of things. Any answer to a question which does not ask or explain the right kind of thing will be philosophically frustrated and dull.

The mind has not merely made a discovery of external fact; it has altered its own character by the attempt to know external fact.

The notion that science and spirituality are forever at war is the invention of twits who understand neither.

The human mind is like a flashlight in the dark. It illuminates a small circle of the world around us, but beyond that circle lies an infinite darkness that we can never fully penetrate.

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.

To know the world one must construct it. One does not go for a walk in order to walk but to construct the world at each step.

The principle of parsimony suggests that entities should not be multiplied beyond necessity; yet in the study of human nature, we continually discover that the simple explanation was merely the one we had grown comfortable defending.

The mind has shown itself capable of grasping the incomprehensible; it has stood in the presence of the infinite and perceived it as finite; it has measured the unmeasurable and found dimensions.

We do not think in words alone. We think in images, in sensations, in the movement and flow of muscle and nerve. Yet we must clothe our thought in words to communicate it, and so our words always betray the living truth a little.

The true nature of things is in their particulars, not in generalities; we know a thing by knowing its individual characteristics, not by subsumming it under a class.

The metaphor of the library is the metaphor of the world. We search for the infinite in the finite, and we find it nowhere but in language itself.

The true nature of things is in their particulars, not in generalities; we know the world through its infinite variations, not through abstract rules that pretend to govern them.

The human understanding is no dry light, but receives an infusion from the will and affections; whence proceed sciences which may be called 'sciences as one would.' For what a man had rather were true he more readily believes.

The most terrible thing about materialism is not that it assumes the world to be made of atoms, but that it assumes this ideal notion of material atoms to be something particularly scientific, particular real, or particularly philosophic.

The true paradox of consciousness is that the more narrowly we examine it, the more it seems to elude us, as if consciousness were not an object to be grasped but a field in which the grasping occurs.

The mind does not work by starting from universal principles and deducing particular consequences; it works the other way, by gathering up particular cases until the accumulated weight of them forces upon us recognition of a universal principle.

Science is organized knowledge. Wisdom is organized life. The coordination of all knowledge and all effort toward the human purpose, the welfare of life, is the purpose of wisdom.

The mind of man has perforce been made analogous to a mirror, or to a vessel, which can be filled with the images or ideas of things external. But this is a most inadequate and false representation of what takes place in the mind when it is occupied with the pursuit of truth.

The true paradox of consciousness is that it cannot be fully grasped by introspection alone; the observer is always part of the observed, creating an irreducible gap between the thinking subject and its own thought.

The world is everything that is the case. The world is the totality of facts, not of things.

The most incomprehensible thing about the world is that it is comprehensible.

The mind is furnished with a set of instincts which seek out certain kinds of phenomena and are peculiarly sensitive to their presence, and which, once awakened, work and grow by exercise. Our forefathers had convictions; we have only opinions.

The mind is furnished with a set of instincts which seek out certain kinds of phenomena and are apt to feel snubbed or startled by others. The truth is that there are as many 'kinds' of things in the world as there are kinds of interest among observers of it.

The mind is furnished with a set of instincts which seek out certain kinds of phenomena and are careless of others. It is theoretically interested in some matters, theoretically indifferent to others. And, by an easy extension of the principle, what is theoretically indifferent may be, and usually is, theoretically obnoxious.

The mind is furnished with a set of instincts which seek out certain kinds of things in the world—food, safety, beauty, knowledge—and the universe cooperates by containing those things. But there are other things in the universe that do not call to any instinct, that have no utility, that simply exist in their own right.

The true function of philosophy is not to provide final answers, but to keep alive in us the sense of wonder at the world and our place in it.

The true paradox of the human condition is that we are simultaneously utterly insignificant and infinitely precious—strangers to the universe yet the only part of it that knows itself.

Man can embed himself in history only by understanding the way his ancestors embedded themselves in it; but he can understand his ancestors only by re-creating their experiments in his own mind and life.

We are not the measure of all things. There is much in the world that is indifferent to human purposes, and this indifference is a kind of freedom—for us and for reality itself.