Dan, To say t he laws of physics are the same on Earth as on Mars or as they were when the galaxies were being formed, is not to make a sociological statement about the comparative state of science among Earth scientists, little green men & disembodied scientists floating around billions of years ago. Rather it’s to say that the same laws apply here & there, now & then. If astronomers discover a new galaxy forming, they study it for clues to how our own galaxy formed. Why? Only because they think the same laws will apply (i.e., interaction between similar phenomena will be similar under similar conditions.)
[Dan] > the passage from ZMM concerning gravity might shed some light on this. "For > example, it seems completely natural to presume that gravitation and the law > of gravitation existed before Isaac Newton. It would sound nutty to think that until the seventeenth century there was no gravity." "Of course." "So when did this law start? Has it always existed?" John is frowning, wondering what I am getting at. "What I’m driving at," I say, "is the notion that before the beginning of the earth, before the sun and the stars were formed, before the primal generation of anything, the law of gravity existed." "Sure." "Sitting there, having no mass of its own, no energy of its own, not in anyone’s mind because there wasn’t anyone, not in space because there was no space either, not anywhere...this law of gravity still existed?" Now John seems not so sure. "If that law of gravity existed," I say, "I honestly don’t know what a thing has to do to be nonexistent. It seems to me that law of gravity has passed every test of nonexistence there is. You cannot think of a single attribute of nonexistence that that law of gravity didn’t have. Or a single scientific attribute of existence it did have. And yet it is still ‘common sense’ to believe that it existed." John says, "I guess I’d have to think about it." "Well, I predict that if you think about it long enough you will find yourself going round and round and round and round until you finally reach only one possible, rational, intelligent conclusion. The law of gravity and gravity itself did not exist before Isaac Newton. No other conclusion makes sense. "And what that means," I say before he can interrupt, "and what that means is that that law of gravity exists nowhere except in people’s heads! (RMP, ZMM, Chap. 3) [Reconstructed] Z1) The law of gravity cannot exist except in someone’s mind (= understanding). Z2) The law of gravity did not exist in anyone’s mind before Newton . Z3) (Newtonian) gravity is what is understood through (Newtonian) law of gravity. Z4) :. The law of gravity and gravity itself did not exist before Isaac Newton. Q1) What is an example of gravity? A1) An apple falling on Newton ’s skull. Q2) What is an ancient example of gravity? A2) An apple falling on Plato’s skull. How do we reconcile Z4 with A2 (i.e., that gravity doesn’t exist at a time when we have examples of it)? Because we have 2 different notions of gravity. Craig Moq_Discuss mailing list Listinfo, Unsubscribing etc. http://lists.moqtalk.org/listinfo.cgi/moq_discuss-moqtalk.org Archives: http://lists.moqtalk.org/pipermail/moq_discuss-moqtalk.org/ http://moq.org.uk/pipermail/moq_discuss_archive/
