Causality and Chance in Modern Physics

by David Bohm

In this classic, David Bohm was the first to offer us his causal interpretation of the quantum theory. Causality and Chance in Modern Physics continues to make possible further insight into the meaning of the quantum theory and to suggest ways of extending the theory into new directions.

Genres: Science, Physics, Philosophy, Nonfiction, Collections

184 pages, Paperback

First published January 1, 1971

About the author

David Joseph Bohm (December 20, 1917 – October 27, 1992) was an American scientist who has been described as one of the most significant theoretical physicists of the 20th century and who contributed innovative and unorthodox ideas to quantum theory, neuropsychology and the philosophy of mind.

Reviews

[Hantz FV · Rating 5 out of 5]

"Bohm showed explicitly how parameters could indeed be introduced, into nonrelativistic wave mechanics, with the help of which the indeterministic description could be transformed into a deterministic one. More importantly, in my opinion, the subjectivity of the orthodox version, the necessary reference to the “observer”, could be eliminated. ...

But why then had Born not told me of this “pilot wave”? If only to point out what was wrong with it? Why did von Neumann not consider it? More extraordinarily, why did people go on producing “impossibility” proofs, after 1952, and as recently as 1978?... Why is the pilot wave picture ignored in text books? Should it not be taught, not as the only way, but as an antidote to the prevailing complacency? To show us that vagueness, subjectivity, and indeterminism, are not forced on us by experimental facts, but by deliberate theoretical choice?"
- John Stewart Bell

A brilliant defence of dialectical materialism against reductionism and mechanical thinking, particularly in modern (quantum) physics. Though Bohm never explicitly names that philosophy it is obvious he was a conscious dialectician. He even added a whole section on "becoming"!

This book was written to provide a philosophical argument against the common interpretation of the quantum theory and the elevation of Heisenberg's uncertainty to an objective quality of matter instead of a limitation in our current understanding and tools.

BASICALLY (don't @ me for this, I'm not a physicist) Heisenberg uncertainty principle says that the more accurately the position of a particle can be determined, the less precisely its momentum can be measured and vice versa. This uncertainty arises from the very method we have to use to measure those properties. To observe the position of a particle through a microscope, it needs to be interacted with, for example by hitting it with a particle of light. By interacting with the particle, its properties (momentum and position) are inevitably modified from what they were initially. What we measure is the "final" values of these properties. But we don't know well enough how much hitting the particle with light will disturb it. So we can not get the initial values by doing some type of "initial = final - delta". The deviation can be reduced more and more so that the results are as close to the initial values as possible. This can be done for example by hitting the particle with less and less energy. BUT! The less energy the light you use to see the particle has, the blurrier the picture you will get because low energy light means longer wavelengths. A very imprecise and limited analogy to taking pictures with long exposure can be made here. If on the other hand the wavelength is shortened then you have more energy and the disturbance caused by hitting the observed particle with light is greater. So you can get a more accurate (less blurry) position but the deviation caused is greater. So we either have blurry pictures of accurate things or sharp pictures of altered things.

However with a large enough number of samples these properties can be predicted on average fairly precisely with the help of statistical laws.

Now this limitation, which is obviously one having to do with our current methods and understanding of the quantum theory, has been elevated as a final limitation on our ability to understand the world. With Heisenberg saying we can never go beyond this. And some who came after him even claimed that we can not even conceive of ways to go beyond that limitation. Therefore our only way of knowing about subatomic particles is statistical and NOT causal, going as far as to entirely reject causality and to elevate probability as the most fundamental type of law to which every causal relation can be reduced.

In this text David Bohm exposes the errors of this conception. And shows that the viewpoint and limitation taken on the results of the experiments in quantum physics is backed mostly by a philosophical standpoint. And with a different method the same experiments instead of spelling a limit on human knowledge on the contrary opens new paths for us to explore. For example that there can be more fundamental levels of matter to be discovered and studied to understand the phenomena at the quantum level. Levels that would provide new properties to help understand position and momentum of a particle instead of reducing these two properties to the absolute and final ones.

He shows how reductionism is consistently creeping up in science with scientists trying to elevate every new method or set of laws to the absolute. An attitude which does not correspond with the basic tenets of science or even with reality, which is shown by every experiment to be infinitely small and infinitely big.

His own interpretation of the quantum theory which he discovered independently of de Broglie posits that instead of entities acting now as particles and now as waves, we are dealing with entities were both those properties exist simultaneously regardless of observation. Which one is manifested depends on which type of observation is made but the observation doesn't fundamentally change the thing observed. And to this day even if it's not the most popular viewpoint (YET!!) every new experiment seem to vindicate it. Last year there was a lot of noise about the physics Nobel laureates (2022 - https://www.nobelprize.org/prizes/phy...) demonstrating that ~reality is not locally real~, meaning that ruling out *local* hidden variables doesn't remove all the ~quantum weirdness~. Bohm's theory is one of hidden variables, but it's a *non-local* theory, meaning that ~things influence each other beyond the limits of the speed of light~.

BASICALLY (again do NOT @ me)
Local: interactions below or at the speed of light
Non-local: the opposite

This is a really good introduction to modern physics that is fairly accessible with some basic understanding of physics. He's an amazing communicator of science.

[Shea Levy · Rating 5 out of 5]

In this book, David Bohm explores the concepts of causality, chance, and natural law as they arise in and apply to physics. After a general overview presenting his views on the subject and contrasting them with the mechanism/reductionism that is common amongst physicists, he explores the development of classical, relativistic, and quantum physics through both lenses. In discussing quantum mechanics, he concludes that the usual (Copenhagen) interpretation requires abandoning concepts of causality and objective reality in order to preserve the assumptions of mechanistic philosophy, and presents the outline of an alternative interpretation that doesn't have these problems. He finishes with an exploration of rejecting what he sees as the core assumption of mechanism (that everything can be completely understood/explained in terms of a finite set of basic properties, characteristics, laws, entities, etc.) and what implications that rejection has for how we should do science.

Bohm's writing is clear and engaging, and he lays out some very compelling evidence and reasoning for adopting his world view. The precision of his terminology, the depth of his engagement with the available evidence, etc. are superb, and the overall metaphysical and epistemological picture he paints seems very well supported by my other experiences and knowledge. Rejecting reductionism and absolute knowledge without falling into relativism or total skepticism is no easy task, but Bohm pulls it off.

Bohm is probably most well-known to my audience for his eponymous interpretation of quantum mechanics, and while he does briefly touch on it in this book I want to point out that this book is not primarily about de Broglie–Bohm theory. The theory itself is not explored in significant detail, nor do the ideas presented depend on the particular truth of that particular interpretation. In this work, Bohm presents it as merely a demonstration of the possibility of another way and an interesting candidate for further exploration of these ideas in this specific context, not as a decisive stance.

I did have three gripes with this book, though to be fair only one is really Bohm's fault. First, some of the footnotes in the kindle edition were buggy, either not existing at all or not linking to the right places. Second, it was written before QCD and the standard model and contains speculations about what resolutions to the problem of a sudden explosion of subatomic/subnucleonic particles might look like that don't appear to have been borne out. The serious objection is that some of Bohm's language smuggles in the assumptions of absolute contextless knowledge that he is trying to reject, weakening his case. In particular, in describing e.g. Newton's laws as "approximate" and "having errors" implies some ultimate true exact model, even if it can never be attained. I would have instead said something like: In some contexts (e.g. firing a rocket) they are correct, in some (e.g. calculating the precession of the perihelion of Mercury) they are approximate, and in some (e.g. electrons moving at 0.999 c) they do not apply.

Overall, I strongly recommend this book to anyone interested in philosophy of science or epistemology. I'd say especially so to anyone who considers themselves a reductionist, but considering who is reading this that's basically the same group. Reading this in high school first opened me up to the possibility of a non-reductionistic scientific mindset, and re-reading it now has solidified my belief that such a mindset is not only possible but preferable/better justified given the evidence currently available.

[Ed · Rating 5 out of 5]

I think this is the best book about the fundamental assumptions of science I have ever read. David Bohm is one of the wisest and open-minded thinkers I've ever encountered. He believes that science should be based on the assumption of the "qualitative infinity of nature." We shouldn't assume that anything is what it is absolutely. "Any given set of qualities and properties of matter and categories of laws expressed in terms of these qualities and properties is applicable only within limited contexts, over limited ranges of conditions and to limited degrees of approximation...." The continued existence of any entity or property depends on a balance of the processes tending to change it in different directions. "The broader the context or longer period of time, the more opportunity for that balance to be fundamentally altered." This is consistent with what the process philosophers have told us: Being is just an abstraction from becoming.

Scientific laws can apply only conditionally, not absolutely; they are always subject to revision. We should doubt that any description of "elementary particles" or statement of laws governing them could constitute a full and final description of reality. We should also doubt that we can know the universe's future: "the prediction of the 'heat death' of the universe will probably be invalidated by qualitatively new developments reflecting the inexhaustible and infinite character of the universal process of becoming."

Much of Bohm's book is a critique of the philosophy of mechanism, which he regards as an unjustified extrapolation from science's success in discovering certain conditional mechanistic relationships. Mechanism aims to reduce everything to interactions between basic entities with fixed qualities, like the parts of a machine. This overlooks another kind of relation, the "reciprocal relationship" between an entity and the broader context that makes it what it is. The earliest forms of mechanism were deterministic, assuming that the future could be calculated from the initial positions and velocities of entities and the forces acting upon them. Bohm does not confine his critique to deterministic mechanism, but extends it to the indeterministic mechanism of quantum mechanics. The conventional interpretation of QM attributes an absolute and final validity to the indeterminacy principle, so that only a statistical description of reality is permitted and no causal interpretation of phenomena is even pursued. Bohm regards causality and chance--necessary causes and chance contingencies--as two aspects of all processes. Any theory that embraces one to the exclusion of the other is inherently incomplete. "Neither causal laws nor laws of chance can ever be perfectly correct, because each inevitably leaves out some aspect of what is happening in broader contexts." That's why Bohm has led the search for a "hidden variables" interpretation of QM. In the end, Bohm regards the mechanistic philosophy in all its forms as contrary to the spirit of scientific inquiry, since it tends to regard a limited truth as the whole truth. "The essential character of scientific research is that it moves towards the absolute by studying the relative, in its inexhaustible multiplicity and diversity."

In contrast to the mechanistic philosophy, Bohm proposes a more holistic and organic view. "The inter-relationships of the parts (or sub-wholes) within a system depend crucially on the state of the whole, in a way that is not expressible in terms of properties of the parts alone. Indeed, the parts are organized in ways that flow out of the whole. The usual mechanistic notion that the organization, and indeed, the entire behaviour, of the whole derives solely from the parts and their predetermined inter-relationships thus breaks down."

Recommended for readers interested in theoretical physics or the philosophy of science.

[Andrew Davis · Rating 3 out of 5]

A quite interesting outlook on the modern quantum theory. My notes follow.
In quantum theory an environment has to be understood as \underline{an undivided whole} not just from the properties of its parts solely. In other words we cannot determine behaviour from pre-existent parts related in pre-determined ways.

All the objects are \underline{enfolded} in the overall field and there is a constant movement of unfoldement and enfoldement, in which they are created, sustained and ultimately dissolved.

Each element is internally related to the whole, in the sense that the whole is actively enfolded in it.

The necessary relationships between objects, events, conditions at a given time and those at later times are termed \underline{causal laws}.

Lord Kelvin expressed the opinion that the basic general outline of physical theories was pretty well settled and that there remained only "two small clouds" on the horizon, namely:
\begin{enumerate}
\item the negative results of the Michelson-Morley experiment, and
\item the failure of Rayleigh-Jeans law to predict the distribution of radiant energy in a black body
\end{enumerate}
The first one led to theory of relativity and the second one to quantum theory.

In quantum theory the principle of complementarity states that we are restricted to complementary pairs of imprecisely defined concepts, such as:
\begin{itemize}
\item position and momentum,
\item wave and particle
\end{itemize}
and therefore that no sigle overall concept is supposed ever to be possible.

Electron is a combination of particle and field, interconnected and undergoing suitable random fluctuations in its motions.

The fact that wave and particle are never found separately suggest instead that they are both different aspects of some fundamentally new kind of entity which is likely to be quite different from a simple wave or a simple particle, but which leads to these two limiting manifestations as approximations that are valid under appropriate conditions.

There is much evidence that the field acts as a wave and yet shows a tendency to produce discrete and particle like concentrations of energy, charge, momentum, mass, etc.

At a lower level, the particle does not move as a permanently existing entity, but is formed in a random way by suitable concentrations of the field energy.

It is evident then, that the entire scheme by which the universe is regarded as made of certain kinds of elementary particles has demonstrated its inadequacy, and that some very different concept is needed here.

[Christine Cordula Dantas · Rating 5 out of 5]

An excellent book by David Bohm, intertwining physics and philosophy (a rare combination in these days), in a clear, interesting viewpoint, with a well-written historical development of fundamental concepts. His criticism and unique view of science, as nicely described in this text, make it an obligatory reading for professionals as well as the general reader. His philosophical position, highlighting the infinitely qualitative nature of the Universe, reminded me of Spinoza, Schelling; and Bergson, in the sense of the novelty of time, brought by quantitative and qualitative physical processes and their various interconnections at several levels. The only drawback is to be somewhat repetitive in certain points, but otherwise a 4.5/5 star book.

[Keerthana · Rating 2 out of 5]

This book took me a month to get through. I had vaguely heard of Bohm's "pilot wave theory" and I picked this up to hear of it from the horse's mouth.

Unfortunately, I feel like it left a lot wanting. Bohm is a scientific writer, not necessarily an engaging one. He spends a lot of time ensuring that the points he makes are precise and concrete, but more often than not, this resulted in him saying the same thing over and over again. And worst of all, in spite of this attempt, the book was very vague- it raised some valid criticisms of the Copenhagen interpretation and how we take the uncertainity principle to be valid even at lower levels of physical laws (which, fair enough, and it did lead me down a rabbit hole). But doesn't expand in very much detail alternative deterministic laws. Or at least, not to the level of detail that I would've liked to see and can reasonably expect from a book like this.

It is a good critique of practices in theoretical research that I don't really have the knowledge to refute. And I really like the way it changed how I think about physical laws- I have found myself applying it in my day-to-day life too. But my GOD did it put me in a reading slump. Agonizing to get through. Sorry Bohm

[Jansen Tan · Rating 5 out of 5]

David Bohm brilliantly describes dialectic materialism and sharply criticizes mechanism.

And as Bohm describes the dialectic materialist philosophy, he does so by using examples from various scientific fields; thus implicitly demonstrating that all science is fundamentally an exercise in dialectic materialism.

Furthermore, in chapters 4 and 5, Bohm argues that only by studying dialectic materialism, by understanding it, and by applying it to scientific activities will humanity be able to develop physics.

[Vishal · Rating 5 out of 5]

This is a very interesting book thinking deep about what is known as "absolute truth". It starts from high level abstractions and delves deep into the conception of science. The thought process is very similar to the old Upanishadic viewpoint of what is defined as "Existence" itself.
I recommend reading this book as a contemplation on what it means to "do science".

[Silvester Borsboom · Rating 4 out of 5]

Erg gaaf en diep, zowel vanuit natuurkundig als filosofisch oogpunt.

[Thomas Atwood · Rating 4 out of 5]

This is a book for physicists and philosophers. I found the first four chapters informative and enlightening, especially regarding the current interpretations of quantum mechanics and the reasons why some of the assumptions behind it are flawed. The fifth and final chapter was entirely philosophical and frankly I found it to be somewhat obvious and boring. So I rate this book as four stars for four really well conceived and well written chapters out of five.

[Kelly · Rating 3 out of 5]

I read and enjoyed the first three chapters. Interesting philosophy of science. The fourth chapter was too science heavy for me, over my head, and I put it down.