I’m starting a new thread on this, because the “Predictability” thread is already quite long.
In that earlier thread, I wrote:
to which @dga471 responded:
What I had noticed, was that Newtonian mechanics was a major reconceptualization. The older common sense view of motion must have been that moving things tended to slow down and stop. Newton’s first law said something quite contrary to that.
Once I realized that Newton was reconceptualizing motion, then it became clear Newton’s laws were not descriptions, they were definitions of his new conceptualization. And if those laws are definitions, then they become logical truths once we accept those definitions. So they cannot imply determinism. Definitions cannot have determinism as a consequence.
Here’s another way of explaining the difference, which I will over-dramatize.
According to the traditional view, Newton’s laws govern the behavior of objects, particles, etc.
We imagine particle A sensing that there is some force. So particle A pulls out his measuring instruments to measure the force, and then consults with Newton’s laws to compute the needed rate of acceleration toward particle B.
In the alternative view, particle A accelerates toward particle be because it feels like it. Maybe particle A and particle B are in love. The scientists observes that acceleration, and thereby ascribes a force of attraction, in accordance with f=ma. Thus the role of Newton’s laws is to govern the ascribing behavior of scientists.
With this alternative view, Newton’s laws are solving what philosophers might call an intentionality problem. The laws tell us how to use that terminology from physics, so that our sentences are about something (some aspect of the world). The laws tell us how to ascribe properties (such as force, mass) to reality. That ascribing of properties is usually known as “measurement”. And it is the measurements, rather than the laws, that are descriptions of reality. Newton’s laws work so well because they have vastly enhanced our ability to have accurate measurements (i.e. descriptions).
When we use Newton’s laws to make predictions, what we are really predicting are other measurements that we might make. And because the laws provide the meanings of our terminology, they enable us to understand what our predicted measurements tell us about reality.