Alexandre Koyré


Alexandre Koyré : biography

29 August 1892 – 28 April 1964

Koyré focused on Galileo, Plato, and Isaac Newton. His most famous work is From the Closed World to the Infinite Universe, a series of lectures given at The Johns Hopkins University in 1959 on the rise of early modern science and the change of scientists’ perception of the world during the period from Nicholas of Cusa and Giordano Bruno through Newton. Though the book has been widely heralded, it was a summation of Koyré’s perspective rather than an original new work.

Koyré was suspicious of scientists’ claims to prove natural or fundamental truths through experiments. He argued these experiments were based on complicated premises, and that they tended to prove the outlook behind these premises, rather than any real truth. He repeatedly critiqued Galileo’s experiments, claiming that some of them could not have taken place, and brought into question the results Galileo claimed and which modern historians of science had hitherto accepted.

According to Koyré, it was not the experimental or empirical nature of Galileo’s and Newton’s discoveries that carried the Scientific Revolution of the 16th and 17th centuries, but a shift in perspective, a change in theoretical outlook toward the world. Koyré strongly criticized what he called the “positivist” notion that science should only discover given phenomena, the relations between them and certain laws that would help to describe or predict them. To Koyré science was, at its heart, theory: an aspiration to know the truth of the world, of uncovering the essential structures from which phenomena, and the basic laws that relate them, spring.

Koyré was also interested in the correlations between scientific discoveries and religious or philosophical world views. Not unlike Husserl in his later studies, Koyré claimed that modern science had succeeded in overcoming the split, inherent in traditional Aristotelian science, between Earth and Space, since these were now both seen as governed by the same laws. On the other hand, another split had now been created, between the phenomenal world inhabited by man and the purely abstract, mathematical world of science. Koyré aimed to show how this “first world”, the world of human dwelling (personal and historical), apparently irrelevant to modern naturalistic research, was by no means irrelevant for the very constitution and development of this research. Koyré consistently sought to show how scientific truth is always discovered in correlation with specific historical, even purely personal, circumstances.

Koyré’s work can be seen as a systematic analysis of the constitutive achievements that resulted in scientific knowledge, but with particular emphasis on the historical, and specifically human, circumstances that generate the scientists’ phenomenal world and serve as foundation for all scientific constitutions of meaning.

Koyré influenced major European and American philosophers of science, most significantly Thomas Kuhn, Imre Lakatos and Paul Feyerabend. In 1961 he was awarded the Sarton Medal by the History of Science Society.


In the course of his studies of Galileo, Koyré famously claimed that the experiments with weights falling and rolling on inclined planes that Galileo described in his writings probably had not been carried out in practice, but where instead thought experiments intended to illustrate his deductions. Koyré argued that the precision of the results reported by Galileo was not possible with the technology available to him and quoted the contemporary judgment of Marin Mersenne, who had questioned the feasibility of reproducing Galileo’s results. Furthermore, according to Koyré, Galileo’s science was largely a product of his Platonist philosophy and did not really derive from experimental observations.

Koyré’s conclusions were first challenged in 1961 by Thomas B. Settle, who as a graduate student at Cornell University succeeded in reproducing Galileo’s experiments with inclined planes using the methods and technologies described in Galileo’s writing. Later, Stillman Drake and others worked through Galileo’s notes and demonstrated that Galileo was a careful experimentalist whose observations did play the role in the development of his scientific system that he later claimed in his published work.