Alberto Vanzo writes…<\/b><\/p>\n
In an essay<\/a> that he published anonymously, Newton used the distinction between experimental and speculative philosophy<\/a> to attack Leibniz. Newton wrote: “The Philosophy which Mr. Newton in his Principles and Optiques has pursued is Experimental<\/em>.” Newton went on claiming that Leibniz, instead, “is taken up with Hypotheses, and propounds them, not to be examined by experiments, but to be believed without Examination.”<\/p>\n Leibniz did not accept being classed as a speculative armchair philosopher. He retorted<\/a>: “I am strongly in favour of the experimental philosophy, but M. Newton is departing very far from it”.<\/p>\n In this post, I will discuss what Leibniz’s professed sympathy for experimental philosophy amounts to. Was Newton right in depicting him as a foe of experimental philosophy?<\/p>\n To answer this question, let us consider four typical features of early modern experimental philosophers:<\/p>\n Did Leibniz have the four typical features of experimental philosophers?<\/p>\n First, he declared his sympathy for experimental philosophy in passage quoted at the beginning of this post.<\/p>\n Second, Leibniz had the same friends and foes of experimental philosophers. He praised Bacon for ably introducing \u201cthe art of experimenting\u201d. Speaking of Robert Boyle\u2019s air pump experiments, he called him \u201cthe highest of men\u201d. He also criticized Descartes in the same terms as British philosophers:<\/p>\n Third, the natural-philosophical method of the mature Leibniz displays many affinities with the method of experimental philosophers. To know nature, a \u201ccatalogue of experiments is to be compiled\u201d [source<\/a>]. We must write Baconian natural histories. Then we should \u201cinfer a maximum from experience before giving ourselves a freer way to hypotheses\u201d (letter to P.A. Michelotti, 1715). This sounds like the two-stage method that experimental philosophers advocated: first, collect data; second, theorize on the basis of the data.<\/p>\n Fourth, Leibniz embraces the rhetoric of experimental philosophers, but only in part. He places great importance on experiments and observations. However, he does not criticize hypotheses, speculations, or demonstrative reasonings from first principles as such. This is because demonstrative, a priori reasonings play an important role in Leibniz’s natural philosophy.<\/p>\n Leibniz thinks that we can prove some general truths about the natural world a priori: for instance, the non-existence of atoms and the law of equality of cause and effect. More importantly, a priori reasonings are necessary to justify our inductive practices.<\/p>\n When experimental natural philosophers make inductions, they presuppose the truth of certain principles, like the principle of the uniformity of nature: \u201cif the cause is the same or similar in all cases, the effect will be the same or similar in all\u201d. Why should we take this and similar principles to be true? Leibniz notes:<\/p>\n\n
if Descartes had relied less on his imaginary hypotheses and had been more attached to experience, I believe that his physics would have been worth following<\/em> […] (Letter to C. Philipp, 1679)<\/ol>\n