Explanation of Newtonian Time

Matt Farr posted a new paper on Time in Classical Physics:

Wigner (1995, 334) describes how Newton’s “most important” achievement was the division of the world into “Initial Conditions and Laws of Nature”, noting that “[b]efore Newton there was no sharp separation between the two concepts. […] After Newton’s time the sharp separation of initial conditions and laws of nature was taken for granted and rarely even mentioned.” This is the central feature of the Newtonian schema.

Some people are so locked into this view that they say that indeterminism and free will are inconceivable. When you make a choice at a restaurant menu, it has to be determined by the initial conditions, or else the laws of physics are violated. No, that is just the Newtonian schema.

For example, Sabine Hossenfelder argues:

And according to new scientist, the superdeterminist view 5:20 naturally raises the possibility that the laws of physics are at odds with unlimited free will. 5:26 What are we to make of this? For one thing, this free will assumption in quantum physics, despite 5:33 its name, has nothing to do with what we normally refer to as free will in none of the definitions 5:40 that philosophers like to use.

Regardless of what you think quantum physics exactly means, the laws 5:47 of physics are always at odds with unlimited free will. This is why they're called laws. If you jump 5:54 off a bridge, you'll fall down. And no amount of free will is going to make you fall up.

She is saying that the Newtonian schema leaves no room for free will. If your initial conditions have you jumping off a bridge, the laws of physics determine your fall, and free will cannot do anything.

I think she is alluding to philosophers who try to define free will as being compatible with all your choices being determined before you were born. To those philosophers, free will is just in your imagination, and has nothing to do with the laws of physics or any actual choices you make. Most philosophers have such a nihilist view.

Yes, the Newton schema assumes that the past determines the future. That is not a law of physics. It is just an assumption. It works well approximately in a great many cases. Not all cases, if you believe in free will.

Some people also argue that the future can determine the past, in the same way that the past determines the future.

The above paper looks at what Newton said about time, and contrasts it with relativity and Lagrangian mechanics. Everyone says Newtonian time is more intuitive than relativistic time, but I am not sure. I have no intuition for anything going faster than light, as Newtonian time allows.

Lagrangian mechanics is another story. Time is just another variable, and it is not so clear how causality works. The paper tries to make sense of it.

New Scientist just released a video:

What Is Reality? Does Quantum Physics Have The Answer?

Over the past century, quantum physics has transformed science and reshaped our understanding of reality. In this special compilation from the New Scientist archive, we trace that evolution, from the birth of quantum mechanics to today’s lab-made “mini universes.”

We explore how quantum ideas revolutionised technology, how they continue to inspire new forms of creativity, and how recent breakthroughs are pushing the limits of what we can understand.

Most of it is not too bad, but it presents an expert physicist saying, about interpretations of quantum mechanics:

I think the 5:02 one that is probably most compelling to 5:04 the majority of physicists is called the 5:06 many worlds interpretation. It's 5:08 compelling because it says that 5:09 fundamentally we are also in superposition. Every possibility has a 5:14 realization in different worlds.

No, this is crazy stuff. I hope it is not true that a majority of physicists find this nuttiness compelling.

The Schroedinger Cat was once an example of silly thinking. Now this man is compelled to believe in many-worlds because he wants to believe that he is just like a Schroeding cat.