This article discusses new material, published in volume 12 of the Collected Papers of Albert Einstein, that addresses Einstein’s knowledge of the Michelson–Morley experiment prior to 1905: in a lecture in Chicago in 1921, Einstein referred to the experiment, mentioned when he came upon it and hinted at its influence. Arguments are presented to explain the contrast with Einstein’s later pronouncements on the role of the experiment.

: Some of the great physicists' belief in the existence of a connection between the aesthetical features of a theory (such as beauty and simplicity) and its truth is still one of the most intriguing issues in the aesthetics of science. In this paper I explore the philosophical credibility of a version of this thesis, focusing on the connection between the mathematical beauty and simplicity of a theory and its truth. I discuss a heuristic interpretation of this thesis, attempting to (...) clarify where the appeal of this Pythagorean view comes from and what are the arguments favoring its acceptance or rejection. Along the way, I sketch the historical context in which this heuristic interpretation gained credibility (the quantum crisis in physics in the 1920s), as well as the more general implications of this thesis for physicists' metaphysical outlook. (shrink)

I discuss the role of beauty in physics. Physicists are sometimes described as platonists for their conviction that the fundamental laws are elegant and aesthetic arguments represent an important epistemic tool. After a review of the ideas of Plato and some of the leading figures of modern physics, which suggest that this is indeed the case, I present a list of current aesthetic criteria. I focus on symmetry and unity and demonstrate their increasing relevance in an array of experimentally verified (...) theories. I also deal with an open issue of naturalness as the third criterion. The laws of nature appear increasingly beautiful as we uncover them, and it is important to see if the trend continues in the future. (shrink)

Gerald Holton has famously described Einstein’s career as a philosophical “pilgrimage”. Starting on “the historic ground” of Machian positivism and phenomenalism, following the completion of general relativity in late 1915, Einstein’s philosophy endured (a) a speculative turn: physical theorizing appears as ultimately a “pure mathematical construction” guided by faith in the simplicity of nature and (b) a realistic turn: science is “nothing more than a refinement ”of the everyday belief in the existence of mind-independent physical reality. Nevertheless, Einstein’s mathematical constructivism (...) that supports his unified field theory program appears to be, at first sight, hardly compatible with the common sense realism with which he countered quantum theory. Thus, literature on Einstein’s philosophy of science has often struggled in finding the thread between ostensibly conflicting philosophical pronouncements. This paper supports the claim that Einstein’s dialog with Émile Meyerson from the mid 1920s till the early 1930s might be a neglected source to solve this riddle. According to Einstein, Meyerson shared (a) his belief in the independent existence of an external world and (b) his conviction that the latter can be grasped only by speculative means. Einstein could present his search for a unified field theory as a metaphysical-realistic program opposed to the positivistic-operationalist spirit of quantum mechanics. (shrink)

During the last decade new developments in theoretical and speculative cosmology have reopened the old discussion of cosmology's scientific status and the more general question of the demarcation between science and non-science. The multiverse hypothesis, in particular, is central to this discussion and controversial because it seems to disagree with methodological and epistemic standards traditionally accepted in the physical sciences. But what are these standards and how sacrosanct are they? Does anthropic multiverse cosmology rest on evaluation criteria that conflict with (...) and go beyond those ordinarily accepted, so that it constitutes an “epistemic shift” in fundamental physics? The paper offers a brief characterization of the modern multiverse and also refers to a few earlier attempts to introduce epistemic shifts in the science of the universe. It further discusses the several meanings of testability, addresses the question of falsifiability as a sine qua non for a theory being scientific, and briefly compares the situation in cosmology with the one in systematic biology. Multiverse theory is not generally falsifiable, which has led to proposals from some physicists to overrule not only Popperian standards but also other evaluation criteria of a philosophical nature. However, this is hardly possible and nor is it possible to get rid of explicit philosophical considerations in some other aspects of cosmological research, however advanced it becomes. (shrink)

Metaphysicians frequently appeal to the idea that theoretical simplicity is truth conducive in metaphysics, in the sense that, all other things being equal, simpler metaphysical theories are more likely to be true. In this paper I defend the notion that theoretical simplicity is truth conducive in metaphysics, against several recent objections. I do not give any direct arguments for the thesis that simplicity is truth conducive in metaphysics, since I am aware of no such arguments. I do argue, however, that (...) there is no special problem with the notion that simplicity is truth conducive in metaphysics. More specifically, I argue that if you accept the idea that simplicity is truth conducive in science, then it would be objectionably arbitrary to reject the idea that simplicity is truth conducive in metaphysics. (shrink)

The paper offers a historical overview of Einstein's oscillating attitude towards a "phenomenological" and "dynamical" treatment of rods and clocks in relativity theory. Contrary to what it has been usually claimed in recent literature, it is argued that this distinction should not be understood in the framework of opposition between principle and constructive theories. In particular Einstein does not seem to have plead for a "dynamical" explanation for the phenomenon rods contraction and clock dilation which was initially described only "kinematically". (...) On the contrary textual evidence shows that, according to Einstein, a realistic microscopic model of rods and clocks was needed to account for the very existence of measuring devices of "identical construction" which always measure the same unit of time and the same unit of length. In fact, it will be shown that the empirical meaningfulness of both relativity theories depends on what, following Max Born, one might call the "principle of the physical identity of the units of measure". In the attempt to justify the validity of such principle, Einstein was forced by different interlocutors, in particular Hermann Weyl and Wolfgang Pauli, to deal with the genuine epistemological, rather then physical question whether a theory should be able or not to described the material devices that serve to its own verification. (shrink)

In this opinion piece, the authors offer their personal and idiosyncratic views of the future of the philosophy of science, focusing on its relationship with the history of science and metaphysics, respectively. With regard to the former, they suggest that the Kantian tradition might be drawn upon both to render the history and philosophy of science more relevant to philosophy as a whole and to overcome the challenges posed by naturalism. When it comes to the latter, they suggest both that (...) metaphysics has much to learn from the philosophy of science and that it offers an array of tools that philosophers of science can themselves appropriate. (shrink)

While Plantinga has famously argued that acceptance of neo-Darwinian theory commits one to the rejection of naturalism, Plantinga’s argument is vulnerable to an objection developed by Evan Fales. Not only does Fales’ objection undermine Plantinga’s original argument, it establishes a general challenge which any attempt to revitalize Plantinga’s argument must overcome. After briefly laying out the contours of this challenge, we attempt to meet it by arguing that because a purely naturalistic account of our etiology cannot explain the correlation between (...) our preference for simplicity and simplicity’s ability to serve as a veridical method of theory selection, the scientific realist is committed to the rejection of naturalism. (shrink)

This article concerns the way in which philosophers study the epistemology of scientific thought experiments. Starting with a general overview of the main contemporary philosophical accounts, we will first argue that two implicit assumptions are present therein: first, that the epistemology of scientific thought experiments is solely concerned with factual knowledge of the world; and second, that philosophers should account for this in terms of the way in which individuals in general contemplate these thought experiments in thought. Our goal is (...) to evaluate these assumptions and their implications using a particular case study: Albert Einstein's magnet-conductor thought experiment. We will argue that an analysis of this thought experiment based on these assumptions – as John Norton (1991) provides – is, in a sense, both misguided (the thought experiment by itself did not lead Einstein to factual knowledge of the world) and too narrow (to understand the thought experiment's epistemology, its historical context should also be taken into account explicitly). Based on this evaluation we propose an alternative philosophical approach to the epistemology of scientific thought experiments which is more encompassing while preserving what is of value in the dominant view. (shrink)

This paper takes as its point of departure two striking incongruities between scientiªc practice and trends in modern history and philosophy of science. (1) Many modern historians of science are so preoccupied with local scientiªc practices that they fail to recognize important non-local elements. (2) Many modern philosophers of science make a sharp distinction between explanation and evidence, whereas in scientiªc practice explanatory power is routinely used as evidence for scientiªc claims. I draw attention to one speciªc way in..

This paper will serve as the editorial note on Einstein's 1916 review article on general relativity in a planned volume with all of Einstein's papers in Annalen der Physik. It summarizes much of my other work on history of general relativity and draws heavily on the annotation of Einstein's writings and correspondence on general relativity for Vols. 4, 7, and 8 of the Einstein edition.

I consider the question of how literally one can construe the “gauge argument,” which is the canonical means of understanding the putatively central import of local gauge symmetry principles for fundamental physics. As I argue, the gauge argument must be afforded a heuristic reading. Claims to the effect that the argument reflects a deep “logic of nature” must, for numerous reasons I discuss, be taken with a grain of salt.

ArgumentEinstein's initial fame came in late 1919 with a dramatic breakthrough in his general theory of relativity. Through a remarkable confluence of events and circumstances, the mass media soon projected an image of the photogenic physicist as a bold new revolutionary thinker. With his theory of relativity Einstein had overthrown outworn ideas about space and time dating back to Newton's day, no small feat. While downplaying his reputation as a revolutionary, Einstein proved he was well cast for the role of (...) mild-mannered scientific genius. Yet fame demanded its price. Surrounded by social and economic unrest in Berlin, he was caught between two worlds, one struggling to be born, another refusing to die. Far from withdrawing, he threw himself into the political fray to become a symbol for international reconciliation during the early Weimar Republic. A decade later, his public image acquired another layer when he re-emerged as a Stoic sage and selfless humanitarian, a quasi-religious figure who saw himself as a modern-day Spinoza. Focusing on events of this period and the role of the German media in portraying them, this essay highlights the scientific and political undercurrents that drew Einstein into the public eye at a critical juncture in European history. Its broader aim is to show the import of these themes within the context of the vast literature on Einstein as well as the larger historiography of science. (shrink)

This article deals with the question whether aesthetic considerations affected Einstein in formulating both his theories of relativity. The opinions of philosophers and historians alike are divided on this matter. Thus, Gerald Holton supports the view that Einstein employed aesthetic considerations in formulating his theory of special relativity whereas Jim Shelton opposes it, one of his reasons being that Einstein did not mention such considerations. The other theory, namely, that of general relativity, is discussed by John D. Norton. He asserts (...) that the successful completion of this theory was due to Einstein's adherence to mathematical simplicity resulting from experience, as Einstein himself stated, and not from an aesthetic drive, to which he did not refer. The present work attempts to overcome this deficiency indirectly by investigating Einstein's aesthetic awareness and its consequences for his work. It is found that this awareness was imbedded in his perception of nature and is linked to the criteria (such as simplicity) that guided him in formulating his theories. The conclusion thus reached is that aesthetic considerations did play a role in Einstein's endeavour, contrary to the assertions of Shelton and Norton. (shrink)

I consider the question of how literally one can construe the “gauge argument,” which is the canonical means of understanding the putatively central import of local gauge symmetry principles for fundamental physics. As I argue, the gauge argument must be afforded a heuristic reading. Claims to the effect that the argument reflects a deep “logic of nature” must, for numerous reasons I discuss, be taken with a grain of salt.

During the last decade new developments in theoretical and speculative cosmology have reopened the old discussion of cosmology’s scientific status and the more general question of the demarcation between science and non-science. The multiverse hypothesis, in particular, is central to this discussion and controversial because it seems to disagree with methodological and epistemic standards traditionally accepted in the physical sciences. But what are these standards and how sacrosanct are they? Does anthropic multiverse cosmology rest on evaluation criteria that conflict with (...) and go beyond those ordinarily accepted, so that it constitutes an “epistemic shift” in fundamental physics? The paper offers a brief characterization of the modern multiverse and also refers to a few earlier attempts to introduce epistemic shifts in the science of the universe. It further discusses the several meanings of testability, addresses the question of falsifiability as a sine qua non for a theory being scientific, and briefly compares the situation in cosmology with the one in systematic biology. Multiverse theory is not generally falsifiable, which has led to proposals from some physicists to overrule not only Popperian standards but also other evaluation criteria of a philosophical nature. However, this is hardly possible and nor is it possible to get rid of explicit philosophical considerations in some other aspects of cosmological research, however advanced it becomes. (shrink)

In this opinion piece, the authors offer their personal and idiosyncratic views of the future of the philosophy of science, focusing on its relationship with the history of science and metaphysics, respectively. With regard to the former, they suggest that the Kantian tradition might be drawn upon both to render the history and philosophy of science more relevant to philosophy as a whole and to overcome the challenges posed by naturalism. When it comes to the latter, they suggest both that (...) metaphysics has much to learn from the philosophy of science and that it offers an array of tools that philosophers of science can themselves appropriate. (shrink)

We discuss Einstein’s knowledge of projective geometry. We show that two pages of Einstein’s Scratch Notebook from around 1912 with geometrical sketches can directly be associated with similar sketches in manuscript pages dating from his Princeton years. By this correspondence, we show that the sketches are all related to a common theme, the discussion of involution in a projective geometry setting with particular emphasis on the infinite point. We offer a conjecture as to the probable purpose of these geometric considerations.