cousin_it comments on Social ethics vs decision theory - Less Wrong

3 Post author: AlexMennen 20 February 2011 04:14AM

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Comment author: cousin_it 23 February 2011 01:42:01AM *  0 points [-]

Sorry. I deleted my comment because it sounded too obvious. (For onlookers, I said the energy gets spent due to shaking of the arm.)

And FWIW, the shaking (cycling of tension level in the relevant muscles) can't provide net energy to the object because you apply as much work to it on the up movements as it applies to you on the downward movements.

Of course it doesn't provide net energy to the object, but it still takes energy away from you. You spend it on the upward movements, but don't reclaim it on the downward movements because that would involve resynthesizing ATP or whatever. So it becomes heat. Likewise, braking your car doesn't cause refuelling (except when it does).

Comment author: SilasBarta 23 February 2011 05:09:42PM 0 points [-]

In the context of the hypothetical physicists, it does not help them resolve their confusion to point to the hand shaking. Their mistake is in only counting the work done by the hand to the object. Once they've made that mistake, telling them that the hand shakes would not change their minds, since it doesn't show net work being done by the body in that respect, which is why I made the comment you quoted.

The mistake could only be corrected by pointing out the incorrect model of how humans generate lifting force.

So while your point is correct, and perhaps obvious, one should also remember that it doesn't address the specific mistake I criticized.

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