Bruce,
I think you conceded too much in this message. In the previous message you wrote eventually Einstein found a deep 'explanation' for gravity >> in terms of the effects that matter has on space itself But grant writes: Did he not theorize that gravity is a force that > curves space-time nearby rather than acting on other masses at a distance? to which you essentially assent. But it's MASS that curves space, not gravity, no? Isn't "gravity" unnecessary? A gratuitous mystery? N -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bruce Sherwood Sent: Friday, May 18, 2012 9:16 PM To: Grant Holland Cc: The Friday Morning Applied Complexity Coffee Group Subject: Re: [FRIAM] Unsolved Problems in Psychology Yes, that's what I meant in citing Einstein. As for the specifics of the case, Einstein realized that action at a distance was not consistent with the Special Theory of Relativity, that nothing could be communicated at a speed greater than the speed of light. If something suddenly yanked our Sun far away from us, it would be eight minutes before the sunlight vanished (the Sun is about 8 light-minutes away from us), and it would also be eight minutes before our orbit changed from circular to a straight line. It was these considerations among others that led Einstein to seek a theory of gravity, which is now called the General Theory of Relativity. Bruce On Fri, May 18, 2012 at 9:10 PM, Grant Holland < <mailto:[email protected]> [email protected]> wrote: > Bruce, > > Did not Einstein put "action at a distance" wrt gravity to rest with > his general theory? Did he not theorize that gravity is a force that > curves space-time nearby rather than acting on other masses at a distance? > > Just askin' > Grant > > > On 5/18/12 4:13 PM, Bruce Sherwood wrote: >> >> Newton famously said about action at a distance, "I frame no >> hypotheses". I take this to mean something like the following: >> >> "I completely agree with you that I haven't explained gravity. Rather >> I've shown that observations are consistent with the radical notion >> that all matter attracts all other matter, here and in the heavens, >> made quantitative by a one-over-r-squared force 'law'. On this basis >> I have shown that the orbits of the planets and the behavior of the >> tides and the fall of an apple, previously seen as completely >> different phenomena, are 'explainable' within one single framework. >> >> I propose that we provisionally abandon the search for an >> 'explanation' of gravity, which looks fruitless for now, and instead >> concentrate on working out the consequences of the new framework. >> Let's leave it as a task for future scientists to try to understand >> at a deeper level than 'action-at-a-distance' what the real character >> of gravity is. There has been altogether too much speculation, such >> as maybe angels push the planets around. Let's get on with studying >> what we can." >> >> I think Newton doesn't get nearly enough credit for this radical >> standpoint, which made it possible to go forward. And of course we >> know that eventually Einstein found a deep 'explanation' for gravity >> in terms of the effects that matter has on space itself. There are >> hints in the current string theory community of even deeper insights >> into the nature of gravity. >> >> Bruce >> >> On Fri, May 18, 2012 at 1:38 PM, Russ Abbott< <mailto:[email protected]> [email protected]> >> wrote: >>> >>> John, I like your gravity question. If this were Google+, I'd click >>> its >>> +1 >>> button. My wife, who studies these things, says that one of the >>> fiercest contemporary criticisms of Newton's theories was that they >>> depended on a mysterious (magical?) action at a distance. >>> >>> -- Russ Abbott >> >> ============================================================ >> >> FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at >> cafe at St. John's College lectures, archives, unsubscribe, maps at >> <http://www.friam.org> http://www.friam.org ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at <http://www.friam.org> http://www.friam.org
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