To Explain the World: The Discovery of Modern Science by Steven Weinberg
Book: To Explain the World: The Discovery of Modern Science by Steven Weinberg
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so he sidestepped the issue, and published what he did understand. This is just about what a physicist would do today, but aside from its application of mathematics to physics, what does it have to do with Descartes’ Discourse on Method ? I can’t see any sign that he was following his own prescriptions for “Rightly Conducting One’s Reason and of Seeking Truth in the Sciences.”
I should add that in his Principles of Philosophy Descartes offered a significant qualitative improvement to Buridan’s notion of impetus. 7 He argued that “all movement is, of itself, along straight lines,” so that (contrary to both Aristotle and Galileo) a force is required to keep planetary bodies in their curved orbits. But Descartes made no attempt at a calculation of this force. As we will see in Chapter 14 , it remained for Huygens to calculate the force required to keep a body moving at a given speed on a circle of given radius, and for Newton to explain this force, as the force of gravitation.
In 1649 Descartes traveled to Stockholm to serve as a teacher of the reigning Queen Christina. Perhaps as a result of the cold Swedish weather, and having to get up to meet Christina at an unwontedly early hour, Descartes in the next year, like Bacon,died of pneumonia. Fourteen years later his works joined those of Copernicus and Galileo on the Index of books forbidden to Roman Catholics.
The writings of Descartes on scientific method have attracted much attention among philosophers, but I don’t think they have had much positive influence on the practice of scientific research (or even, as argued above, on Descartes’ own most successful scientific work). His writings did have one negative effect: they delayed the reception of Newtonian physics in France. The program set out in the Discourse on Method, of deriving scientific principles by pure reason, never worked, and never could have worked. Huygens when young considered himself a follower of Descartes, but he came to understand that scientific principles were only hypotheses, to be tested by comparing their consequences with observation. 8
On the other hand, Descartes’ work on optics shows that he too understood that this sort of scientific hypothesis is sometimes necessary. Laurens Laudan has found evidence for the same understanding in Descartes’ discussion of chemistry in the Principles of Philosophy. 9 This raises the question whether any scientists actually learned from Descartes the practice of making hypotheses to be tested experimentally, as Laudan thought was true of Boyle. My own view is that this hypothetical practice was widely understood before Descartes. How else would one describe what Galileo did, in using the hypothesis that falling bodies are uniformly accelerated to derive the consequence that projectiles follow parabolic paths, and then testing it experimentally?
According to the biography of Descartes by Richard Watson, 10 “Without the Cartesian method of analyzing material things into their primary elements, we would never have developed the atom bomb. The seventeenth-century rise of Modern Science, the eighteenth-century Enlightenment, the nineteenth-century Industrial Revolution, your twentieth-century personal computer, and the twentieth-century deciphering of the brain—all Cartesian.” Descartes did make a great contribution to mathematics,but it is absurd to suppose that it is Descartes’ writing on scientific method that has brought about any of these happy advances.
Descartes and Bacon are only two of the philosophers who over the centuries have tried to prescribe rules for scientific research. It never works. We learn how to do science, not by making rules about how to do science, but from the experience of doing science, driven by desire for the pleasure we get when our methods succeed in explaining something.
14
The Newtonian Synthesis
With Newton we come to the climax of the scientific revolution. But what an odd bird to be cast in
I should add that in his Principles of Philosophy Descartes offered a significant qualitative improvement to Buridan’s notion of impetus. 7 He argued that “all movement is, of itself, along straight lines,” so that (contrary to both Aristotle and Galileo) a force is required to keep planetary bodies in their curved orbits. But Descartes made no attempt at a calculation of this force. As we will see in Chapter 14 , it remained for Huygens to calculate the force required to keep a body moving at a given speed on a circle of given radius, and for Newton to explain this force, as the force of gravitation.
In 1649 Descartes traveled to Stockholm to serve as a teacher of the reigning Queen Christina. Perhaps as a result of the cold Swedish weather, and having to get up to meet Christina at an unwontedly early hour, Descartes in the next year, like Bacon,died of pneumonia. Fourteen years later his works joined those of Copernicus and Galileo on the Index of books forbidden to Roman Catholics.
The writings of Descartes on scientific method have attracted much attention among philosophers, but I don’t think they have had much positive influence on the practice of scientific research (or even, as argued above, on Descartes’ own most successful scientific work). His writings did have one negative effect: they delayed the reception of Newtonian physics in France. The program set out in the Discourse on Method, of deriving scientific principles by pure reason, never worked, and never could have worked. Huygens when young considered himself a follower of Descartes, but he came to understand that scientific principles were only hypotheses, to be tested by comparing their consequences with observation. 8
On the other hand, Descartes’ work on optics shows that he too understood that this sort of scientific hypothesis is sometimes necessary. Laurens Laudan has found evidence for the same understanding in Descartes’ discussion of chemistry in the Principles of Philosophy. 9 This raises the question whether any scientists actually learned from Descartes the practice of making hypotheses to be tested experimentally, as Laudan thought was true of Boyle. My own view is that this hypothetical practice was widely understood before Descartes. How else would one describe what Galileo did, in using the hypothesis that falling bodies are uniformly accelerated to derive the consequence that projectiles follow parabolic paths, and then testing it experimentally?
According to the biography of Descartes by Richard Watson, 10 “Without the Cartesian method of analyzing material things into their primary elements, we would never have developed the atom bomb. The seventeenth-century rise of Modern Science, the eighteenth-century Enlightenment, the nineteenth-century Industrial Revolution, your twentieth-century personal computer, and the twentieth-century deciphering of the brain—all Cartesian.” Descartes did make a great contribution to mathematics,but it is absurd to suppose that it is Descartes’ writing on scientific method that has brought about any of these happy advances.
Descartes and Bacon are only two of the philosophers who over the centuries have tried to prescribe rules for scientific research. It never works. We learn how to do science, not by making rules about how to do science, but from the experience of doing science, driven by desire for the pleasure we get when our methods succeed in explaining something.
14
The Newtonian Synthesis
With Newton we come to the climax of the scientific revolution. But what an odd bird to be cast in
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