Five-minute digest
The Problems of Philosophy
Summary
The Problems of Philosophy is a short introduction to philosophy, chiefly to the theory of knowledge, written for a general reader. Russell opens by asking whether there is any knowledge so certain that no reasonable person could doubt it, and the fifteen chapters work toward a qualified answer. The first chapters take an ordinary table. Its colour, shape and texture vary with the light, the observer's position and the sense used, so what we directly know are sense-data, not the table itself. Is there a real, physical table behind them? Russell reviews Descartes's method of doubt and Berkeley's idealism, which holds that objects exist only as ideas in minds, and argues that although we cannot strictly prove that matter exists, the belief in independent physical objects is an instinctive belief that best explains our experience. Physical objects are known only by their structure, through correspondences with our sense-data, not by their intrinsic nature. Chapter V draws the book's best-known distinction: knowledge by acquaintance, the direct awareness of sense-data, memories, our own thoughts and universals, and knowledge by description, our knowledge of things such as Bismarck or Julius Caesar through definite descriptions built from what we are acquainted with. Every proposition we can understand, he holds, must be composed of constituents with which we are acquainted. The middle chapters turn to general principles. Our expectation that the sun will rise tomorrow rests on the principle of induction, which experience can neither prove nor disprove; the chicken fed daily until the day its neck is wrung shows the risk of crude expectations. Russell considers the laws of logic, the debate between empiricists and rationalists, and Kant's attempt to explain a priori knowledge, which he finds unsatisfactory. He then defends a realm of universals in the tradition of Plato, arguing that relations such as being north of are neither physical nor mental yet real, and that a priori knowledge concerns relations of universals. The later chapters treat intuitive and self-evident knowledge, truth as correspondence between belief and fact (illustrated by Othello's false belief that Desdemona loves Cassio), the difference between knowledge, error and probable opinion, and the limits of metaphysical systems such as Hegel's that claim to prove the nature of the universe as a whole. The last chapter, on the value of philosophy, argues that philosophy is valuable less for answers than for its questions, which free the mind from the tyranny of custom and enlarge it through contemplation of the universe. The book was written in 1911 and published in 1912 in the Home University Library series; Russell's preface acknowledges the unpublished work of G. E. Moore and J. M. Keynes.
Top Lessons
Starting from the ordinary
Russell begins not with a grand theory but with the table in front of him, showing that the most familiar object raises hard questions about what we really perceive. Philosophy, on this view, begins in careful attention to the commonplace.
Knowing a thing and knowing about it
Chapter V separates acquaintance, direct awareness, from description, knowledge reached through true statements about something. Most of what we know about people, places and the past is knowledge by description.
The problem of induction
Every expectation that the future will resemble the past, from the rising sun to the laws of science, rests on a principle that experience cannot prove. Russell's chicken makes the point memorably, and his answer is that the principle must be accepted on its intrinsic evidence or not at all.
Why philosophy matters
In Chapter XV Russell answers the practical man who asks what philosophy is for. Its value, he argues, lies in freeing us from unexamined prejudice and in enlarging the self through contemplation of what is not the self.
Verified Quotes
Frequently cited
“Is there any knowledge in the world which is so certain that no reasonable man could doubt it?”
“And we know that even from a given point of view the colour will seem different by artificial light, or to a colour-blind man, or to a man wearing blue spectacles”
“questions which increase the interest of the world, and show the strangeness and wonder lying just below the surface even in the commonest things of daily life.”
Frequently cited
“The man who has fed the chicken every day throughout its life at last wrings its neck instead, showing that more refined views as to the uniformity of nature would have been useful to the chicken.”
“The value of philosophy is, in fact, to be sought largely in its very uncertainty.”
Frequently cited
“The man who has no tincture of philosophy goes through life imprisoned in the prejudices derived from common sense, from the habitual beliefs of his age or his nation, and from convictions which have grown up in his mind without the co-operation or consent of his deliberate reason.”
Frequently cited
“Philosophy is to be studied, not for the sake of any definite answers to its questions, since no definite answers can, as a rule, be known to be true, but rather for the sake of the questions themselves”
Medical Lens
The book is not about medicine, but its early chapters bear on the philosophy of perception that underlies psychiatry and neurology. Russell discusses how sense-data vary with the observer, including colour-blindness and spectacles, and in Chapter III mentions the physiological chain of light, nerves and brain between object and perception. In Chapter II he treats dreams and the possibility that all of life is a dream as the strongest form of skeptical doubt, concluding that it is logically possible but less simple than the common-sense hypothesis. These discussions offer a philosophical background for questions about hallucination and the reliability of perception, though Russell does not address clinical cases.
- Chapter I
The table's appearance varying with light, position, colour-blindness and blue spectacles.
- Chapter II
Dreams and the hypothesis that the whole of life is a dream, weighed against belief in an external world.
- Chapter III
The physical and physiological causes of perception and the gap between physical space and the space of sense-data.