# Newton's "Scholium" and Leibnizian Letters

## February 12th, 2020

- I did NOT do the readings today, unfortunately, and got here a tad late, so this'll be interesting
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- Alright, let's look through Newton's "Scholium" and Leibniz's "Letters to Clarke"
    - Newton is a famous scientist, while Leibniz was a lawyer *and* a famous scientist/philosopher in his own right
    - "All of these philosophical developments were going on at the same time as these political and scientific revolutions, and in many ways undergirded them"

- As we know, Newton came up with the law of gravity, co-discovered calculus, and, interestingly, was one of the first people to rigorously assume that nature followed laws that were universally true
    - So, in Newton's 1st scholium, he talks about "absolute" space, motion, and time - what does he mean?
        - ABSOLUTE SPACE is God's perspective, the whole universe of space where things can exist that doesn't change; it's objective
        - ABSOLUTE TIME is the same throughout the universe, and flows the same everywhere, even if humans measure it inconsistently
        - ABSOLUTE MOTION, then, is a change in absolute space over some period of absolute time - relative motion, then, is motion relative to a different place, and NOT in reference to absolute space

- Okay; let's now talk about Newton's General Scholium
    - On pg. 318, Newton famously says "I frame no hypotheses" - that, since hypotheses meant to explain by guessing, he won't try to explain why gravity happens; instead, he'll just give the exact mathematical description of the motion he observes and not bother trying to explain how it works (...or so he claims)
        - "Spinoza would look at this and say, 'No axioms? No explanations? Bah!'"
        - Historically here, he was reacting to the "vortex" theory that, because motion has to happen by something being pushed, the planets must've been in some sort of cosmic "whirlpool of aether"

- Let's now look at Leibniz's letters to Clarke, a follower and friend of Newton
    - For letter 1, Leibniz is critiquing Newton's idea of absolute space for theological reasons, saying that defining "space" absolutely - rather than relatively - makes something's absolute position kind of meaningless: why wouldn't God have moved everything, say, a meter to the left?
        - Leibniz also critiques Newton's idea of God having to "fix" the universe from time to time to keep it running
    - In the 2nd letter, we see Leibniz saying that if the universe had problems that *needed* his regular intervention (rather than them being by his choice), that's accusing God of not being all-wise, since if he'd known all possibilities he wouldn't have had to choose a course of action that he'd later have to reverse
        - This comes straight from Leibniz's strong view of the PSR: Newton thinks God can act arbitrarily, while Leibniz (and Spinoza) would say that God acts perfectly
    - "Notice here, too, that we have some of the brightest scientists of the day deeply involved with theological issues and religious questions"

- Okay, we're running out of time, but the rest of the letters see Leibniz trying to defend the PSR and using it to defend why things are the way they are

- In the meantime, an assignment's due Monday for group 2, with Group 1's submission due Tuesday night - both are on John Locke. Bye!