Albert Einstein: Philosopher-Scientist

Edited by:
  • Paul Arthur Schilpp
In discussions: Einstein and Bohr in 1930. Credit: niels bohr archive

“Here I sit in order to write, at the age of 67, something like my own obituary.” With these words Albert Einstein starts his only existing autobiography, his “Autobiographical Notes”. Around the middle of the twentieth century the philosopher Paul A. Schilpp published a series of books under the heading “The Library of Living Philosophers”; each contains essays written by one leading philosopher — such as Karl Popper, Bertrand Russell or Jean-Paul Sartre — and by some of his peers.

Einstein's “Autobiographical Notes”, written in German and translated into English by Schilpp, with both versions in the book, are among the most outstanding intellectual reflections ever written. He tells us that “Even when I was a fairly precocious young man the nothingness of the hopes and strivings which chase most men restlessly through life came to my consciousness with considerable vitality”. But he then goes on to ask the humble question, “What, precisely, is ‘thinking’?”. He agrees with the philosopher David Hume that certain concepts, like causality, cannot be deduced, but he disagrees that the specific concepts chosen by Immanuel Kant are indispensable, preferring to call them “freely chosen conventions”.

Einstein discusses many issues. He complains about university education. “It is, in fact, nothing short of a miracle that the modern methods of instruction have not yet entirely strangled the holy curiosity of inquiry.” One can only regret that most countries' education systems have taken the road towards less rather than more freedom as demanded by Einstein.

Later on, Einstein gives us many details of how he was led to his theories of relativity and their fundamental ideas, mentioning most prominently the influence of Ernst Mach. It is very moving when he tells us that by the age of 16 he had realized that if one could proceed alongside a beam of light with the same speed, one would see impossible configurations of electric fields.

Parts of the book have already become classics, for example where Einstein discusses his views of quantum mechanics and where Niels Bohr documents his “Discussions with Einstein about epistemological problems in atomic physics”. The latter is one of the most momentous debates that ever took place. Einstein, while he admits quantum theory is “the most successful physical theory of our period”, nevertheless concludes that it “offers no useful point of departure for future development”. He reaches that conclusion by analysing what he believes physics should be about. For him, “Physics is an attempt conceptually to grasp reality as it is thought independently of its being observed. In this sense one speaks of ‘physical reality’.”

Einstein carefully analyses the situation of two quantum-mechanically correlated, so-called entangled, systems. He points out that observation of one system immediately changes the quantum state of the other regardless of how far apart they are. Yet, as Einstein says, “the real situation” of the second system “must be independent of what happens” to the first system. He decides that “One can escape this conclusion only by either assuming that measurement of one system (telepathically) changes the real situation of the other or by denying independent real situations to such separated systems”. Both alternatives appear to him entirely unacceptable.

Bohr, in his essay, shows beautiful drawings of the gedanken experimental set-ups, like the famous two-slit and photon-in-a-box arrangements, suggested by Einstein in order to show that there is something wrong with quantum physics. In all these cases, Bohr was able to prove Einstein was wrong by analysing exactly what ‘observation’ means. He emphasizes how important it is in physics to analyse precisely what can be said about an experiment. Bohr is acutely aware of the huge potential for misunderstanding and renounces any allusions to mysticism. He also dislikes phrases like “disturbing phenomena by observations” because of their potential for confusion. Bohr stresses the use of “the word phenomenon exclusively to refer to observations made under specific circumstances, including an account of the whole experimental arrangement”. Einstein's desideratum of an independent, real situation then becomes devoid of meaning for his separated quantum systems.

Einstein's philosophical beliefs are carefully analysed in the book by a number of eminent philosophers, for example Philipp Frank, a member of the Vienna Circle. And the essays by V. F. Lenzen and F. S. C. Northrop systematizing some of Einstein's views on the theory of knowledge and his conception of science even merit the master's approval in his “Reply” at the end of the collection. These essays, and Hans Reichenbach's analysis of the philosophical significance of the theory of relativity, make excellent reading for any philosophy seminar.

It is impossible to do justice to all the contributions. Most impressive are Kurt Gödel's proposal of closed-time-like solutions to general relativity which allow one to return from the past even when progressing all the time into the future, and Carl Menger's suggestion that we might ultimately have to give up the idea of a continuum. Georges Lemaître's discussion of the cosmological constant is an example of a topic that has recently come into focus again because of observed hints of an anomalous expansion of the Universe. Lemaître wisely notes that “The history of science provides many instances of discoveries which have been made for reasons which are no longer considered satisfactory”.

In that spirit, we note that quantum entanglement is one such case. Einstein clearly foresaw its enormous philosophical consequences, which motivated him to introduce it in his critique of quantum physics. While that critique can hardly be upheld today, entanglement became the central concept in the newly emerging field of quantum information, which includes such eye-catching topics as teleportation and quantum computation. It is tantalizing to contemplate Einstein's and Bohr's reactions to the enormous experimental progress made in recent years. Realization of many of the old gedanken experiments and their refinements have given rise to a generation of physicists to whom experiments with individual quanta are an everyday experience in the laboratory, and who have thus obtained a natural, intuitive understanding of quantum phenomena.

Bohr, in his essay, mentions the “benefit from the inspiration which we all derive from every contact with Einstein”. This, I promise, will be true for every patient reader of the book, who has a wonderful opportunity to encounter one of the greatest minds of all time.