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Personal Knowledge: Towards a Post-Critical Philosophy

Personal Knowledge: Towards a Post-Critical Philosophy

by Michael Polanyi

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In this work the distinguished physical chemist and philosopher, Michael Polanyi, demonstrates that the scientist's personal participation in his knowledge, in both its discovery and its validation, is an indispensable part of science itself. Even in the exact sciences, "knowing" is an art, of which the skill of the knower, guided by his personal commitment and his


In this work the distinguished physical chemist and philosopher, Michael Polanyi, demonstrates that the scientist's personal participation in his knowledge, in both its discovery and its validation, is an indispensable part of science itself. Even in the exact sciences, "knowing" is an art, of which the skill of the knower, guided by his personal commitment and his passionate sense of increasing contact with reality, is a logically necessary part. In the biological and social sciences this becomes even more evident.

The tendency to make knowledge impersonal in our culture has split fact from value, science from humanity. Polanyi wishes to substitute for the objective, impersonal ideal of scientific detachment an alternative ideal which gives attention to the personal involvement of the knower in all acts of understanding. His book should help to restore science to its rightful place in an integrated culture, as part of the whole person's continuing endeavor to make sense of the totality of his experience. In honor of this work and his The Study of Man Polanyi was presented with the Lecomte de Noüy Award for 1959.

Editorial Reviews

Science and Education

“Rich in insights, groundbreaking in its interpretations, Personal Knowledge deserves to be better known.”
Philosophy Today

“Polanyi’s monumental work, Personal Knowledge: Towards a Post-Critical Philosophy, takes the shape of an orderly rejection of the false ideal of wholly explicit and wholly impersonal, so-called objective knowledge. The human mind, for him, is not an impersonal machine engaged in the manufacture of truth. In fact, Personal Knowledge represents a compelling critique of the positivist claim for total objectivity in scientific knowledge. . . . Polanyi, the scientist-philosopher, calls forth an enormous array of examples to show that the scientist himself is engaged in acts of personal acceptance and judgment in the very doing of science.”

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Personal Knowledge

Towards a Post-Critical Philosophy

By Michael Polanyi

The University of Chicago Press

Copyright © 1962 Michael Polanyi
All rights reserved.
ISBN: 978-0-226-23276-8




IN the Ptolemaic system, as in the cosmogony of the Bible, man was assigned a central position in the universe, from which position he was ousted by Copernicus. Ever since, writers eager to drive the lesson home have urged us, resolutely and repeatedly, to abandon all sentimental egoism, and to see ourselves objectively in the true perspective of time and space. What precisely does this mean? In a full 'main feature' film, recapitulating faithfully the complete history of the universe, the rise of human beings from the first beginnings of man to the achievements of the twentieth century would flash by in a single second. Alternatively, if we decided to examine the universe objectively in the sense of paying equal attention to portions of equal mass, this would result in a lifelong preoccupation with interstellar dust, relieved only at brief intervals by a survey of incandescent masses of hydrogen—not in a thousand million lifetimes would the turn come to give man even a second's notice. It goes without saying that no one—scientists included—looks at the universe this way, whatever lip-service is given to 'objectivity'. Nor should this surprise us. For, as human beings, we must inevitably see the universe from a centre lying within ourselves and speak about it in terms of a human language shaped by the exigencies of human intercourse. Any attempt rigorously to eliminate our human perspective from our picture of the world must lead to absurdity.

What is the true lesson of the Copernican revolution? Why did Copernicus exchange his actual terrestrial station for an imaginary solar standpoint? The only justification for this lay in the greater intellectual satisfaction he derived from the celestial panorama as seen from the sun instead of the earth. Copernicus gave preference to man's delight in abstract theory, at the price of rejecting the evidence of our senses, which present us with the irresistible fact of the sun, the moon, and the stars rising daily in the east to travel across the sky towards their setting in the west. In a literal sense, therefore, the new Copernican system was as anthropocentric as the Ptolemaic view, the difference being merely that it preferred to satisfy a different human affection.

It becomes legitimate to regard the Copernican system as more objective than the Ptolemaic only if we accept this very shift in the nature of intellectual satisfaction as the criterion of greater objectivity. This would imply that, of two forms of knowledge, we should consider as more objective that which relies to a greater measure on theory rather than on more immediate sensory experience. So that, the theory being placed like a screen between our senses and the things of which our senses otherwise would have gained a more immediate impression, we would rely increasingly on theoretical guidance for the interpretation of our experience, and would correspondingly reduce the status of our raw impressions to that of dubious and possibly misleading appearances.

It seems to me that we have sound reasons for thus considering theoretical knowledge as more objective than immediate experience.

(a) A theory is something other than myself. It may be set out on paper as a system of rules, and it is the more truly a theory the more completely it can be put down in such terms. Mathematical theory reaches the highest perfection in this respect. But even a geographical map fully embodies in itself a set of strict rules for finding one's way through a region of otherwise uncharted experience. Indeed, all theory may be regarded as a kind of map extended over space and time. It seems obvious that a map can be correct or mistaken, so that to the extent to which I have relied on my map I shall attribute to it any mistakes that I made by doing so. A theory on which I rely is therefore objective knowledge in so far as it is not I, but the theory, which is proved right or wrong when I use such knowledge.

(b) A theory, moreover, cannot be led astray by my personal illusions. To find my way by a map I must perform the conscious act of map-reading and I may be deluded in the process, but the map cannot be deluded and remains right or wrong in itself, impersonally. Consequently, a theory on which I rely as part of my knowledge remains unaffected by any fluctuations occurring within myself. It has a rigid formal structure, on whose steadfastness I can depend whatever mood or desire may possess me.

(c) Since the formal affirmations of a theory are unaffected by the state of the person accepting it, theories may be constructed without regard to one's normal approach to experience. This is a third reason why the Copernican system, being more theoretical than the Ptolemaic, is also more objective. Since its picture of the solar system disregards our terrestrial location, it equally commends itself to the inhabitants of Earth, Mars, Venus, or Neptune, provided they share our intellectual values.

Thus, when we claim greater objectivity for the Copernican theory, we do imply that its excellence is, not a matter of personal taste on our part, but an inherent quality deserving universal acceptance by rational creatures. We abandon the cruder anthropocentrism of our senses—but only in favour of a more ambitious anthropocentrism of our reason. In doing so, we claim the capacity to formulate ideas which command respect in their own right, by their very rationality, and which have in this sense an objective standing.

Actually, the theory that the planets move round the sun was to speak for itself in a fashion that went far beyond asserting its own inherent rationality. It was to speak to Kepler (sixty-six years after the death of Copernicus) and inspire his discovery of the elliptic path of planets and of their constant angular surface velocity; and to inspire again, ten years later, his discovery of the Third Law of planetary motion, relating orbital distances to orbital periods. And another sixty-eight years later, Newton was to announce to the world that these laws were but an expression of the underlying fact of general gravitation. The intellectual satisfaction which the heliocentric system originally provided, and which gained acceptance for it, proved to be the token of a deeper significance unknown to its originator. Unknown but not entirely unsuspected; for those who wholeheartedly embraced the Copernican system at an early stage committed themselves thereby to the expectation of an indefinite range of possible future confirmations of the theory, and this expectation was essential to their belief in the superior rationality and objective validity of the system.

One may say, indeed, quite generally, that a theory which we acclaim as rational in itself is thereby accredited with prophetic powers. We accept it in the hope of making contact with reality; so that, being really true, our theory may yet show forth its truth through future centuries in ways undreamed of by its authors. Some of the greatest scientific discoveries of our age have been rightly described as the amazing confirmations of accepted scientific theories. In this wholly indeterminate scope of its true implications lies the deepest sense in which objectivity is attributed to a scientific theory.

Here, then, are the true characteristics of objectivity as exemplified by the Copernican theory. Objectivity does not demand that we estimate man's significance in the universe by the minute size of his body, by the brevity of his past history or his probable future career. It does not require that we see ourselves as a mere grain of sand in a million Saharas. It inspires us, on the contrary, with the hope of overcoming the appalling disabilities of our bodily existence, even to the point of conceiving a rational idea of the universe which can authoritatively speak for itself. It is not a counsel of self-effacement, but the very reverse—a call to the Pygmalion in the mind of man.

This is not, however, what we are taught today. To say that the discovery of objective truth in science consists in the apprehension of a rationality which commands our respect and arouses our contemplative admiration; that such discovery, while using the experience of our senses as clues, transcends this experience by embracing the vision of a reality beyond the impressions of our senses, a vision which speaks for itself in guiding us to an ever deeper understanding of reality—such an account of scientific procedure would be generally shrugged aside as out-dated Platonism: a piece of mystery-mongering unworthy of an enlightened age. Yet it is precisely on this conception of objectivity that I wish to insist in this introductory chapter. I want to recall how scientific theory came to be reduced in the modern mind to the rank of a convenient contrivance, a device for recording events and computing their future course, and I wish to suggest then that twentieth-century physics, and Einstein's discovery of relativity in particular, which are usually regarded as the fruits and illustrations of this positivistic conception of science, demonstrate on the contrary the power of science to make contact with reality in nature by recognizing what is rational in nature.


The story is in three parts, of which the first begins long before Copernicus, though it leads straight up to him. It starts with Pythagoras, who lived a century before Socrates. Even so, Pythagoras was a late-comer in science, for the scientific movement was started almost a generation earlier on rather different lines by the Ionian school of Thales. Pythagoras and his followers did not, like the Ionians, try to describe the universe in terms of certain material elements (fire, air, water, etc.) but interpreted it exclusively in terms of numbers. They took numbers to be the ultimate substance, as well as the form, of things and processes. When sounding an octave they believed they could hear the simple numerical ratio of 1:2 in the harmonious chiming of the sounds from two wires whose lengths had the ratio 1:2. Acoustics made the perfection of simple numerical relations audible to their ear. They turned their eyes towards the heavens and saw the perfect circle of the sun and moon; they watched the diurnal rotation of the firmament and, studying the planets, saw them governed by a complex system of steady circular motions; and they apprehended these celestial perfections in the way one listens to a pure musical interval. They listened to the music of the spheres in a state of mystic communion.

The revival of astronomical theory by Copernicus after two millennia was a conscious return to the Pythagorean tradition. While studying law in Bologna, he worked with the professor of astronomy, Novara, a leading Platonist, who taught that the universe was to be conceived in terms of simple mathematical relationships. Then, on his return to Cracow, with the thought of a heliocentric system in his mind, he made a further study of the philosophers and traced his new conception of the universe back to writers of antiquity standing in the Pythagorean tradition.

After Copernicus, Kepler continued wholeheartedly the Pythagorean quest for harmonious numbers and geometrical excellence. In the volume containing the first statement of his Third Law, we can see him speculating intensely on the way the sun, which is the centre of the cosmos and therefore somehow nous (Reason) itself, apprehends the celestial music performed by the planets: 'Of what sort vision is in the sun, what are its eyes, or what other impulse it has ... even without eyes ... for judging the harmonies of the (celestial) motions,' it would be 'for those inhabiting the earth, not easy to conjecture'—yet one may at least dream, 'lulled by the changing harmony of the band of planets', that 'in the sun there dwells an intellect simple, intellectual fire or mind, whatever it may be, the fountain of all harmony'. He even went so far as to write down the tune of each planet in musical notation.

To Kepler astronomic discovery was ecstatic communion, as he voiced it in a famous passage of the same work:

What I prophesied two-and-twenty years ago, as soon as I discovered the five solids among the heavenly orbits—what I firmly believed long before I had seen Ptolemy's Harmonics—what I had promised my friends in the title of this fifth book, which I named before I was sure of my discovery—what sixteen years ago I urged to be sought—that for which I have devoted the best part of my life to astronomical contemplations, for which I joined Tycho Brahe ... at last I have brought it to light, and recognized its truth beyond all my hopes. ... So now since eighteen months ago the dawn, three months ago the proper light of day, and indeed a very few days ago the pure Sun itself of the most marvellous contemplation has shone forth—nothing holds me; I will indulge my sacred fury; I will taunt mankind with the candid confession that I have stolen the golden vases of the Egyptians, in order to build of them a tabernacle to my God, far indeed from the bounds of Egypt. If you forgive me, I shall rejoice; if you are angry, I shall bear it; the die is cast, the book is written, whether to be read now or by posterity I care not; it may wait a hundred years for its reader, if God himself has waited six thousand years for a man to contemplate His work.

What Kepler claimed here about the Platonic bodies was nonsense, and his exclamation about God's having waited for him for thousands of years was a literary fancy; yet his outburst conveys a true idea of the scientific method and of the nature of science; an idea which has since been disfigured by the sustained attempt to remodel it in the likeness of a mistaken ideal of objectivity.

Passing from Kepler to Galileo, we see the transition to a dynamics in which for the first time numbers enter as measured quantities into mathematical formulae. But with Galileo this usage applies only to terrestrial events, while in respect to heavenly motions he still holds the Pythagorean view that the book of nature is written in geometrical characters. In the Two Great Systems of the World (1632), he argues in the Pythagorean tradition from the principle that the parts of the world are perfectly ordered. He still believes that the motion of the heavenly bodies—in fact all natural motion as such—must be circular. Rectilinear motion implies change of place, and this can occur only from disorder to order: that is, either in the transition from primeval chaos to the right disposition of the parts of the world, or in violent motion, i.e. in the endeavour of a body artificially moved to return to its 'natural' place. Once world order is established, all bodies are 'naturally' at rest or in circular motion. Galileo's observations of inertial motion along a plane terrestrial surface were interpreted by him as circular motions around the centre of the earth.

Thus the first century after the death of Copernicus was inspired by Pythagorean intimations. Their last great manifestation was perhaps Descartes's universal mathematics: his hope of establishing scientific theories by the apprehension of clear and distinct ideas, which as such were necessarily true.

But a different line of approach was already advancing gradually, stemming from the other line of Greek thought which lacked the mysticism of Pythagoras, and which recorded observations of all kinds of things, however imperfect. This school, derived from the Ionian philosophers, culminated in Democritus, a contemporary of Socrates, who first taught men to think in materialistic terms. He laid down the principle: 'By convention coloured, by convention sweet, by convention bitter; in reality only atoms and the void.' With this Galileo himself agreed; the mechanical properties of things alone were primary (to borrow Locke's terminology), their other properties were derivative, or secondary. Eventually it was to appear that the primary qualities of such a universe could be brought under intellectual control by applying Newtonian mechanics to the motions of matter, while its secondary qualities could be derived from this underlying primary reality. Thus emerged the mechanistic conception of the world which prevailed virtually unchanged till the end of the last century. This too was a theoretical and objective view, in the sense of replacing the evidence of our senses by a formal space-time map that predicted the motions of the material particles which were supposed to underlie all external experience. In this sense the mechanistic world-view was fully objective. Yet there is a definite change from the Pythagorean to the Ionian conception of theoretical knowledge. Numbers and geometrical forms are no longer assumed to be inherent as such in Nature. Theory no longer reveals perfection; it no longer contemplates the harmonies of Creation. In Newtonian mechanics the formulae governing the mechanical substratum of the universe were differential equations, containing no numerical rules and exhibiting no geometrical symmetry. Henceforth 'pure' mathematics, formerly the key to nature's mysteries, became strictly separated from the application of mathematics to the formulation of empirical laws. Geometry became the science of empty space; and analysis, affiliated since Descartes to geometry, seceded with it into the region beyond experience. Mathematics represented all rational thinking which appeared necessarily true; while reality was summed up in the events of the world which were seen as contingent—that is, merely such as happened to be the case.


Excerpted from Personal Knowledge by Michael Polanyi. Copyright © 1962 Michael Polanyi. Excerpted by permission of The University of Chicago Press.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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Meet the Author

Michael Polanyi (1891–1976) was a Hungarian-British chemist and philosopher, a fellow of the Royal Society, and a fellow of Merton College, Oxford. His many books include Science, Faith, and Society; Knowing and Being; and Meaning, all published by the University of Chicago Press. 

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