On the Motion and Measurement of Water

made it known that from the reading of those codices one finds that Leonardo was always guided by a geometric spirit, whether he wished to analyze an object, link together a chain of reasoning, or generalize his own ideas. He always desired that experience precede the reasoning about things. I shall treat such a subject, he says himself, but first I will conduct some experiments, as it is my principle to cite experience first, and then demonstrate why bodies are compelled to act in this or that manner. This is the method to be followed in the research of the phenomena of nature. It is true that nature begins with reasoning (1), and ends with experience; but no matter: we must take the opposite path; we must, as I said, begin with experience and, by means of it, discover the reason behind it. Thus spoke Leonardo a century before Bacon Francis Bacon (1561–1626), the English philosopher often credited with developing the scientific method. The author is highlighting that Leonardo practiced empirical science long before it was formally established.. In mechanics he knew, among other things, the theory of forces applied obliquely to the lever arm; the respective resistance of ships; the laws of friction original: "strofinamento." Leonardo conducted the first systematic studies of friction, though his work remained unpublished for centuries. given to us later by Amontons Guillaume Amontons (1663–1705), a French physicist who rediscovered the laws of friction in 1699.; the influence of the center

(1) Leonardo may be forgiven for this erroneous proposition The author refers to Leonardo's statement that "nature begins with reasoning." In the 19th-century view, nature is seen as governed by laws that must be discovered, rather than starting with an abstract logic., which he perhaps uttered so as not to directly oppose the prevailing opinion of his times. Today, everyone knows that reasoning is based upon abstract propositions, and that abstract propositions are not true unless they rest upon the observation of facts; thus, reasoning cannot precede experience.