@ACB,
ACB;68893 wrote:As I see it, the latter means that the heat makes the metal expand. It implies force or compulsion.
If we have two clocks, and one always strikes the hour 10 seconds after the other, we do not say that one causes the other to strike. This shows that we distinguish between causation and mere correlation.
Ok then I submit that I don't see any such
forces. I see heat applied to a piece of metal and then I see a piece of metal expand. I don't see anything more than that. Also, the differences between your clock example and heating a piece of metal are a little bit more than you make out.
When I heat a piece of metal,
that piece starts expanding, not some other piece of metal in the next room. Also, pieces of metal don't start expanding absent heat applied directly to them.
On the other hand, your two clocks can chime independantly from each other. I can smash one and the other one still chimes, destroying the correlation completely.
So far, the only difference I've seen is in how strongly and closely correlations are tied. Some are strong, like heating metal and it expanding. Some are weak, like two clocks chiming, or the death of presidents and their election years.