Reading guide for Thurs 11/17:
Dear, Revolutionizing the Sciences, concl. (pp. 168-170)
Newton, Principia, rules and gen. schol., in Matthews anth. (pp. 146-158)
In spite of the reference to the 18th century in its title, Dear’s brief conclusion looks back over the two centuries he covered in the book.
The first two selections from Newton come from the beginning and end of book III (the last book) of the Principia, which he titles "The System of the World." In an introductory paragraph that comes before the first selection, he describes the earlier books of the Principia as mathematical while saying that this one is "philosophical" (in the sense of natural philosophy). It is here that he gives his accounts of planetary motion, and the law of gravitation is not stated until this book.
The "Rules of Reasoning in Philosophy" appeared in this form only in the third edition; originally the first two were mixed with the statements of phenomena (e.g., that Kepler’s third law is observed to hold for the moons of Jupiter and Saturn and for the planets). In later editions these rules were stated separately and two were added.
The "General Scholium" at the end of book III comes at the end of the Principia as a whole. It is probably most famous for Newton’s refusal to attempt to explain the phenomenon of gravity. The claim "I frame no hypotheses" (p. 152) that he makes in this connection is a translation of the Latin "Hypotheses non fingo." This translation dates from an 18th century translation of Newton and it has been suggested that, at the time, the verb "frame" could be used in the way we use "fabricate." The verb "feign" has been suggested as a better translation into contemporary English.
The final selection comes from the last of a series of "queries" that end Newton’s other great scientific work, his Opticks, in which he set out his particle theory of light. The selection in Matthews is at the end of the query. Here is how that query begins:
Quest. 31. Have not the small Particles of Bodies certain Powers, Virtues, or Forces by which they act at a distance, not only upon the Rays of Light for reflecting, refracting, and inflecting them, but also upon one another for producing a great Part of the Phænomena of Nature? For it’s well known, that Bodies act one upon another by the Attractions of Gravity, Magnetism, and Electricity; and these Instances shew the Tenor and Course of Nature, and make it not improbable but that there may be more attractive Powers than these. For Nature is very consonant and conformable to her self. How these Attractions may be perform’d, I do not here consider. What I call Attraction may be perform’d by impulse, or by some other means unknown to me. I use that Word here to signify only in general any Force by which Bodies tend towards one another, whatsoever be the Cause. For we must learn from the Phænomena of Nature what Bodies attract one another, and what are the Laws and Properties of the Attraction, before we enquire the Cause by which the Attraction is perform’d. The Attractions of Gravity, Magnetism, and Electricity, reach to very sensible distances, and so have been observed by vulgar Eyes, and there may be others which reach to so small distances as hitherto escape Observation; and perhaps electrical Attraction may reach to such small distances, even without being excited by Friction.
For when Salt of Tartar runs per Deliquium, is not this done by an Attraction between the Particles of the Salt of Tartar, and the Particles of the Water which float in the Air in the form of Vapours? ...
In between is an almost Baconian twenty-page series of examples of attractive phenomena.