MAN AND THE INDETERMINACIES* JOHN R. PLATTf Understanding the external world is the objective of science, and accurate prediction is the test ofit. Ifwe really understand genetics, we can breed better hybrid corn. Ifwe really understand geology, we can locate minerals and oil. If we really understand the motion of the atmosphere and its water vapor, we can predict the weather. But some ofthe most thought-provoking problems ofscience are those involving "indeterminacy," where accurate prediction for some reason becomes impossible. It is as though a sign said, "Nonsense!—Your prying or your prediction at this point interferes with itself, so your supposed observations orpredictions can no longer be made objectively or meaningfully ." Many ofthese problems are a little bit like my answer to your question whether I will wear my red tie tomorrow morning. I may tell you that I will, but this is an intention, not an objective prediction like predicting rain—and you will immediately show that you know this by laughing at me ifI try to bet with you on it. It is obvious that my knowledge ofthe prediction and the bet would change my performance, and I am likely to wear the red tie or not, as the case may be,just so I will win—or to do the converse to prove my unpredictability. Everyone knows, really, that predictions of one's own conscious decisions are not objective predictions in any scientific sense. The most famous case ofindeterminacy, where getting data for a prediction interacts with the outcome in somewhat the same way, is that of the Heisenberg "uncertainty principle" in atomic physics, which upset the whole philosophical world forty years ago. But indeterminacy and * A chapter from the book The Step to Man, published byJohn Wiley & Sons, Inc.,June, 1966; reprinted by permission. t Acting Director, Mental Health Research Institute, University ofMichigan, Ann Arbor. 67 related questions of prediction also touch many other problems, for example , in areas such as biology and psychology. It is interesting to look at some ofthese problems to seejust what goes wrong with deterministic predictions, and why. This gives us a much clearer view ofwhat questions objective science can meaningfully ask and what it cannot, and what parts oflife must be left out ofthe scientific equation. It appears that several of the non-classical conclusions may be ofcentral importance in understanding the relations between manandman and between man and the universe. The Areas ofDeterminism The concept ofdeterminismis closely bound up with the concept ofthe "isolated system." An isolated system, in astronomy or physics or chemistry , is a body or collection ofbodies—for example, the sun and planets, or the chemicals in a flask—which are supposed to interact in some respect only with each other. It is a system which an observer can either start off or can observe accurately at some initial time, and which can then continue to be observed indefinitely without any appreciable disturbance to its motions or behavior from interactions with the observer himself or with the rest ofthe universe. These conditions are evidently essential in order for determinism to hold, that is, in order for our specification of the initial state ofthe system to suffice for determining its final state accurately at any later time. Ofcourse, isolation from the surroundings is never perfect. The chemicals in the flask boil offinto the air. The earth's tides slow down the moon by amounts that can be measured. Nevertheless, the "isolated system" is a useful and accurate approximation for most ofthe problems we know how to solve in physics and chemistry and engineering; and in fact, that is why we know how to solve them. Ifwe correct for the small disturbances , Newton's laws will predict eclipses and the motions ofplanets or man-made satellites for years or centuries ahead. The planets are heavy bodies, not much affected by the dust in their paths or the sunbeams by which we observe them. Few other predictions in science are as certain as those of the planets, but in most cases the uncertainties are not believed to be due to any breakdown of determinism. Forecasting the weather, for example, is difficult apparently because of the great complexity of...
MAN AND THE INDETERMINACIES* JOHN R. PLATTf Understanding the external world is the objective of science, and accurate prediction is the test ofit. Ifwe really understand genetics, we can breed better hybrid corn. Ifwe really understand geology, we can locate minerals and oil. If we really understand the motion of the atmosphere and its water vapor, we can predict the weather. But some ofthe most thought-provoking problems ofscience are those involving "indeterminacy," where accurate prediction for some reason becomes impossible. It is as though a sign said, "Nonsense!—Your prying or your prediction at this point interferes with itself, so your supposed observations orpredictions can no longer be made objectively or meaningfully ." Many ofthese problems are a little bit like my answer to your question whether I will wear my red tie tomorrow morning. I may tell you that I will, but this is an intention, not an objective prediction like predicting rain—and you will immediately show that you know this by laughing at me ifI try to bet with you on it. It is obvious that my knowledge ofthe prediction and the bet would change my performance, and I am likely to wear the red tie or not, as the case may be,just so I will win—or to do the converse to prove my unpredictability. Everyone knows, really, that predictions of one's own conscious decisions are not objective predictions in any scientific sense. The most famous case ofindeterminacy, where getting data for a prediction interacts with the outcome in somewhat the same way, is that of the Heisenberg "uncertainty principle" in atomic physics, which upset the whole philosophical world forty years ago. But indeterminacy and * A chapter from the book The Step to Man, published byJohn Wiley & Sons, Inc.,June, 1966; reprinted by permission. t Acting Director, Mental Health Research Institute, University ofMichigan, Ann Arbor. 67 related questions of prediction also touch many other problems, for example , in areas such as biology and psychology. It is interesting to look at some ofthese problems to seejust what goes wrong with deterministic predictions, and why. This gives us a much clearer view ofwhat questions objective science can meaningfully ask and what it cannot, and what parts oflife must be left out ofthe scientific equation. It appears that several of the non-classical conclusions may be ofcentral importance in understanding the relations between manandman and between man and the universe. The Areas ofDeterminism The concept ofdeterminismis closely bound up with the concept ofthe "isolated system." An isolated system, in astronomy or physics or chemistry , is a body or collection ofbodies—for example, the sun and planets, or the chemicals in a flask—which are supposed to interact in some respect only with each other. It is a system which an observer can either start off or can observe accurately at some initial time, and which can then continue to be observed indefinitely without any appreciable disturbance to its motions or behavior from interactions with the observer himself or with the rest ofthe universe. These conditions are evidently essential in order for determinism to hold, that is, in order for our specification of the initial state ofthe system to suffice for determining its final state accurately at any later time. Ofcourse, isolation from the surroundings is never perfect. The chemicals in the flask boil offinto the air. The earth's tides slow down the moon by amounts that can be measured. Nevertheless, the "isolated system" is a useful and accurate approximation for most ofthe problems we know how to solve in physics and chemistry and engineering; and in fact, that is why we know how to solve them. Ifwe correct for the small disturbances , Newton's laws will predict eclipses and the motions ofplanets or man-made satellites for years or centuries ahead. The planets are heavy bodies, not much affected by the dust in their paths or the sunbeams by which we observe them. Few other predictions in science are as certain as those of the planets, but in most cases the uncertainties are not believed to be due to any breakdown of determinism. Forecasting the weather, for example, is difficult apparently because of the great complexity of...
But let vis return to our subject proper. A much more serious and interesting attempt to explain the difficulty away was founded by Bohr and Heisenberg on the idea, mentioned above, that there is an unavoidable and uncontrollable mutual interaction between the observer and the observed physical object. Their ratiocination is briefly as follows. The alleged paradox consists in this, that according to the mechanistic view, by procuring an exact knowledge of the configuration and velocities of all the elementary particles in a man's body, including his brain, one could predict his voluntary actions— which thereby cease to be what he believes them to be, namely voluntary. The fact that we cannot actually procure this detailed knowledge is no great help. Even the theoretical predictability shocks us. To this Bohr answers that the knowledge cannot even be procured in principle, not even in theory, because such accurate observation would involve so strong an interference with “the object” (the man's body) as to dissociate it into single particles—in fact kill him so efficiently that not even a corpse would be left for burial. At any rate, no prediction of behaviour would result, before the “object” is far beyond the state of exhibiting any voluntary behaviour. The emphasis is of course on the phrase “in principle”. That the said knowledge cannot actually be procured, not even for the simplest living organism, let alone a higher animal like man, is clear also without quantum theory and uncertainty relation.
In a recent number of Blackfriars (July, 1949) Dr A. W. Gledhill has discussed very competently some aspects of the statistical method as used in modern physics. He has tried to show there ‘that modern physical theory does not contradict the principle of causality’. Having made a study of this subject over quite a number of years, the writer, while agreeing with some of Dr Gledhill’s conclusions, feels nevertheless that there are a few points which have not been covered as adequately as the importance of the subject for modern philosophy seems to warrant. In order to understand the controversy about the validity or non-validity of the principle of causality, which has been initiated by Heisenberg’s uncertainty principle, it is necessary to realise, first of all, that when a physicist speaks about causality, he usually does not mean the same thing as a scholastic philosopher. In scholastic philosophy one distinguishes different kinds of causes, such as the material, the efficient, the final, as well as the formal and exemplary causes. The classical physicist, on the other hand, since the time of Galileo, admits only efficient causes. Let us therefore give a brief sketch of the development of this concept of scientific causality and show the reasons for this limitation. The purpose of a scientific theory is the prediction of events among the natural objects which form the field of enquiry of the particular science concerned. Evidently, the more certain the prediction, the better the theory on which it is based.
In discussing the fundamental sources of unpredictability, I shall concentrate on those indeterminacies that are definitely required by theory. Let me therefore begin \nby eliminating from consideration supposed indeterminacies stemming from doubts that some people may entertain about basic principles or from certain kinds of ignorance that I believe to be temporary and likely to be remedied in the relatively near future. I assume the following: \n1. Quantum mechanics is correct. The formulation and interpretation of quantum mechanics are still undergoing some necessary evolution, especially in order to accommodate quantum cosmology in a comfortable way, but the basic character of quantum mechanics has always been the same and we may suppose it will remain unchanged. \n2. The elementary particles and their interactions obey a definite dynamical law, discoverable by inquiring complex adaptive systems such as the human scientific enterprise. Although the process of discovery involves a sequence of \napproximate schemata, there is an endpoint to the process after a finite amount of research. (Of course, it can never be possible to prove that the resulting unified theory is perfect; one can only verify it in the usual way by comparing predictions to available observations.) Humans may already have found this unified quantum field theory in the form of superstring theory, which has, to begin with, no arbitrary parameters. (Of course, spontaneous symmetry \nbreaking may give rise to some parameters and even to a choice of solutions, with probabilities for the various alternatives. I will deal with that possibility further on.) This second assumption is equivalent to stating that there is no necessary fundamental unpredictability stemming from ignorance of the universal dynamical law. \n3. The density matrix (in the Schrödinger picture) of the universe near the beginning of its expansion is also knowable. It must in any case be comparatively simple and very far from equilibrium. The second law of thermodynamics and the other associated arrows of time are explained by these properties of the initial density matrix along with the fact that the universe is still very young—the interval of ten billion years is extremely short compared with the relaxation time from the special initial condition.
is all about, and not bothering to familiarize themselves in specific detail with the vast accumulation of behavioral data upon which the conclusions ofpsychoanalysis are based. Though specialists in scientific method, they refuse to look through Galileo's telescope [p. 349]. Hospers examines with skill and calmness many of die totally illogical arguments used in this conference, permitting one to end the volume with a faintly restored faith that one day there will be "a free, critical interchange ofviews on die scientific status of psychoanalysis" between philosophers ofscience and psychoanalysts. Ifthere is any lesson to be drawn from this kind ofexhibition, it is that diere is no substitute for firsthand knowledge ofthe method and data ofa discipline as a prerequisite for any critical discussion ofits merit and validity. This may seem like an utterly banal dictum, yet the facts are that it is too often casually disregarded when it comes to the sciences ofhuman behavior. Any taxicab driver will freely volunteer opinions about reasons forjuvenile delinquency, sexual perversions, drug addiction, or dreams—but rarely about astral physics, genetics, or C14 dating. There is a good reason for this; all such matters touch one personally to varying degrees. But the philosopher (and, even more importandy, the physician) must be cautious not to confuse this personal interest and ¦ involvement with the scientific knowledge and detachment necessary for critical judgment . The latter come about only through long experience and diligent study. George L. Engel University ofRochester The Physicist's Conception ofNature. ByWerner Heisenberg.Translated from the German by ArnoldJ. Pomerans. New York: Harcourt, Brace & Co., 1958. Pp. 192. $3.75. This book, written by a famous German scientist, the founder ofquantum mechanics, die discoverer of die uncertainty relations, and die Nobel prize winner in physics for 1933, does not do much credit to die author. The first 67 pages comprise three chapters which apparendy represent an attempt to amalgamate the three speechesdelivered or three articles written on three different occasions at diree different times. It is difficult to date die first two chapters, but die diird one must have been written in 1948, since in it the author refers to a conversation which he had had "some diirty years ago" during die Communist revolt in Munich (1918). The first chapter of the book presents die idea of the three stages of die evolution ofhuman diought about the surrounding world. According to die author, during olden times (ofKepler, etc.) scientists saw die world as die work ofGod. During the nineteendi century die world was existing all for itself, independent ofman. Since the discovery of the uncertainty relations, die man looking at the surrounding world sees his own image in it. The second chapter represents a discussion ofuncertainty relations and contains several interesting ideas (for example, about past and future difference in die case ofvery short time intervals) which may be ofgreat interest to a person trained in die modern quantum theory but will pass unnoticed by a general reader. 158 Book Reviews Perspectives in Biology and Medicine · Autumn 1939 The third chapter discusses die relative advantages ofclassical (i.e., Greek grammar, etc.) and scientific education and presents arguments in favor ofdie former: "Thus, we may say in favour ofclassical education diat it is always a good diing to know the roots, even ifthey may not always be of practical use" (p. 52). However, by die end of the chapter (p. 67) die audior comes to die conclusion: "It does not matter whedier we prefer a classical or a scientific education. What alone matters is our unshakable faidi in the West." The remaining 115 pages ofthe text contain a masterful selection ofquotations from Kepler, Galileo, Newton, Oswald, De Broglie, and others which are supposed to illustrate die ideas ofdie author expressed in die first 67 pages. G. GAMOW University ofColorado The Autobiography of Charles Darwin, 1809-1882. Edited, with Appendix and notes, by his granddaughter Nora Barlow. New York: Harcourt, Brace & Co., 1959. Pp. 253. $4.50. Darwin's autobiography was written mainly in 1876, six years before his death, with additional material inserted during his last yean. When first published in 1887, as part ofthe Life and Letters ofCharles Darwin, edited by his son Francis, it...
But let us return to our subject proper. A much more serious and interesting attempt to explain the difficulty away was founded by Bohr and Heisenberg on the idea, mentioned above, that there is an unavoidable and uncontrollable mutual interaction between the observer and the observed physical object. Their ratiocination is briefly as follows. The alleged paradox consists in this, that according to the mechanistic view, by procuring an exact knowledge of the configuration and velocities of all the elementary particles in a man's body, including his brain, one could predict his voluntary actions—which thereby cease to be. what he believes them to be, namely voluntary. The fact that we cannot actually procure this detailed knowledge is no great help. Even the theoretical predictability shocks us. To this Bohr answers that the knowledge cannot even be procured in principle, not even in theory, because such accurate observation would involve so strong an interference with ‘the object’ (the man's body) as to dissociate it into single particles—in fact kill him so efficiently that not even a corpse would be left for burial. At any rate, no prediction of behaviour would result, before the ‘object’ is far beyond the state of exhibiting any voluntary behaviour.
“But this is dreadful,” Grete Hermann said. “On the one hand, you claim that your knowledge of the Radium B atom is incomplete inasmuch as you cannot tell when and in what direction the electron will be emitted, while, on the other hand, you tell me that your knowledge is complete because, if there were further determinants, you would get into trouble with other experiments. But our knowledge cannot possibly be complete and incomplete at the same time. The whole thing is sheer nonsense… I was wondering why our inability to discover the causes of, say, the emission of an electron means that we must stop searching further. Admittedly, you don’t forbid this search, but you claim that it is futile since no further determining factors can be found. Indeed, you contend that, if only it is formulated in precise mathematical language, the indeterminacy allows a definite prediction in another experiment. And this, too, you claim is borne out by the results. If you argue like that, you turn uncertainty into a physical reality, with an objective character, while, normally speaking, uncertainty is a synonym for ignorance, and as such something purely subjective.”