From @JohnDenker: Galileo is rightly called the father of modern science
because he insisted that the laws of physics must say
/what happens/; they may or may not say /how/ it happens,
and the basic laws almost never say /why/ it happens.
He insisted on divorcing physics from metaphysics and
philosophy.
Newton went to school on Galileo, and when asked "why"
gravity did what it did, he famously answered "Hypotheses
non fingo."
Let's be clear: The three laws of motion do not express
any cause-and-effect relationships. There is a rule that
says the cause must come before the effect, but in the
third law, the action and the reaction happen at exactly
the same time. Similarly in the second law, the F and the
dp/dt happen at exactly the same time. It is nonsensical
to say that dp/dt causes F, and equally nonsensical to
say that F causes dp/dt.
Therefore I was taken aback to see that chapter 7 relies
on the language of cause-and-effect. On page 149 the
title of section 7.1 is "The effect of interactions".
Then the third paragraph in that section talks about
"an interaction that causes objects to accelerate".
Sorry, that's not the right way to say it. I know you
sometimes hear lazy physicists throw around words like
that without necessarily intending to assert a cause-
and-effect relationship ... but that doesn't make it
OK, and I guarantee you that students will take such
words at face value, and come away with profoundly
wrong ideas.
Constructive suggestion: Systematically go through the
whole book hunting for words like "cause", "effect",
"due to" et cetera ... and replace them with something
more correct. For example, "due to" can be replaced
by "associated with".
From @JohnDenker: Galileo is rightly called the father of modern science because he insisted that the laws of physics must say /what happens/; they may or may not say /how/ it happens, and the basic laws almost never say /why/ it happens. He insisted on divorcing physics from metaphysics and philosophy.
Newton went to school on Galileo, and when asked "why" gravity did what it did, he famously answered "Hypotheses non fingo."
Let's be clear: The three laws of motion do not express any cause-and-effect relationships. There is a rule that says the cause must come before the effect, but in the third law, the action and the reaction happen at exactly the same time. Similarly in the second law, the F and the dp/dt happen at exactly the same time. It is nonsensical to say that dp/dt causes F, and equally nonsensical to say that F causes dp/dt.
Therefore I was taken aback to see that chapter 7 relies on the language of cause-and-effect. On page 149 the title of section 7.1 is "The effect of interactions". Then the third paragraph in that section talks about "an interaction that causes objects to accelerate".
Sorry, that's not the right way to say it. I know you sometimes hear lazy physicists throw around words like that without necessarily intending to assert a cause- and-effect relationship ... but that doesn't make it OK, and I guarantee you that students will take such words at face value, and come away with profoundly wrong ideas.
Constructive suggestion: Systematically go through the whole book hunting for words like "cause", "effect", "due to" et cetera ... and replace them with something more correct. For example, "due to" can be replaced by "associated with".
For the next level of detail on all this, see https://www.av8n.com/physics/causation.htm or equivalently http://www.av8n.com/physics/causation.htm