Is time a substance, particle, force or concept? Is it one big “block”, so the future already exists and “now” is subjective? Or is the present the only place that’s real? Are most physicists determinists?

Question

I have studied a little of this in philosophy (metaphysics, epistemology and ontology) but I really need a scientist (preferably a physicist) to break down what we actually know about the world, as I regrettably have no formal education in physics and can’t work this one out on my own. Thanks 🙂

In: Physics

Answer 1

Time is a concept, and that concept can break down in some instances.

We only have any evidence of there being one reality, one universe. So whatever happens in our universe is what really happens. Determinism is debatable because the Heisenberg uncertainty principal prevents us from using the current state of the universe to predict the future. I think a key piece of determinism is the ability to predict the future. We can’t know enough about the universe to make an accurate prediction.

There was an experiment done on relative time where two clocks were synched up perfectly and then one clock was flown around the world on a jet plane. They had different times afterwards! They experienced a different amount of time because one of them was in motion. Which clock is “correct”? This is why time is just a concept. Neither clock is truly correct because humans invented the idea of time. It works well for our lives, but it doesn’t hold up in all cases.