Chapter III (2)

Natural Philosophy divided into Speculative and Practical. The Necessity of keeping these Two Branches distinct

BUT to leave natural theology, and proceed to natural philosophy; as it was well said by Democritus, that “the knowledge of nature lies concealed in deep mines and caves”; and by the alchemists, that “Vulcan is a second nature, imitating concisely what the first takes time and circuit to effect”; suppose natural philosophy were divided, as it regards the mine and the furnace, and two offices of philosophers, miners, and smelters introduced? This, indeed, may appear jocular, yet such a kind of division we judge extremely useful, when proposed in just and familiar terms; so that the doctrine of nature be divided into speculative and practical, or the search after causes, and the production of effects: the one entering into the bowels of nature, and the other forming her upon the anvil. Nor are we insensible of the strict union between causes and effects; so that the explanation of them must, in some measure, be coupled together: but as all solid and fruitful natural philosophy hath both an ascending and a descending scale of parts, leading from experience to axioms, and from axioms to new discoveries, it seems most advisable here, in the division of sciences, to separate speculation from operation, and treat them distinct.