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Re: [Phys-l] Newton and causation




On Jan 11, 2011, at 3:16 PM, John Denker wrote:

On 01/11/2011 12:47 PM, ludwik kowalski wrote:

change in momentum = impulse

does not address the issue "what causes what."

Agreed!

But I suspect that
Newton did address the issue. He probably wrote that change in
momentum results from an impulse.

Absolutely not.

Newton, like Galileo before him, emphatically explained that the
laws of motion do not say anything about causation.

Can someone to either confirm or
refute this?

I quote from http://www.isaacnewton.ca/gen_scholium/scholium.htm

But hitherto I have not been able to discover the cause of those
properties of gravity from phænomena, and I frame no hypotheses.....
And to us it is enough, that gravity does really exist, and act
according to the laws which we have explained, and abundantly
serves to account for all the motions of the celestial bodies,
and of our sea.

I do not have an easy access to his Principia.

It's online in dozens of places.

http://www.google.com/search?q=%22hypotheses+non+fingo%22

THANK YOU JOHN.D.

Why is it easier, for me, to say the "impulse causes change a in momentum" and not the "impulse results from a changes in momentum." I am probably not the only one to be "preconditioned" to think in terms of causes and effects.

Ludwik

http://csam.montclair.edu/~kowalski/life/intro.html