Followup to: Timeless Physics, Timeless Causality, Thou Art Physics

People hear about many-worlds, which is deterministic, or about timeless physics, and ask:

If the future is determined by physics, how can anyone control it?

In Thou Art Physics, I pointed out that since you are within physics, anything you control is necessarily controlled by physics. Today we will talk about a different aspect of the confusion, the words "determined" and "control".

The "Block Universe" is the classical term for the universe considered from outside Time. Even without timeless physics, Special Relativity outlaws any global space of simultaneity, which is widely believed to suggest the Block Universe—spacetime as one vast 4D block.

When you take a perspective outside time, you have to be careful not to let your old, timeful intuitions run wild in the absence of their subject matter.

In the Block Universe, the future is not determined before you make your choice. "Before" is a timeful word. Once you descend so far as to start talking about time, then, of course, the future comes "after" the past, not "before" it.

If we're going to take a timeless perspective, then the past and the future have not always been there. The Block Universe is not something that hangs, motionless and static, lasting for a very long time. You might try to visualize the Block Universe hanging in front of your mind's eye, but then your mind's eye is running the clock while the universe stays still. Nor does the Block Universe exist for just a single second, and then disappear. It is not instantaneous. It is not eternal. It does not last for exactly 15 seconds. All these are timeful statements. The Block Universe is simply there.

Perhaps people imagine a Determinator—not so much an agent, perhaps, but a mysterious entity labeled "Determinism"—which, at "the dawn of time", say, 6:00am, writes down your choice at 7:00am, and separately, writes the outcome at 7:02am. In which case, indeed, the future would be determined before you made your decision...

In this model, the Determinator writes the script for the Block Universe at 6:00am. And then time—the global time of the universe—continues, running through the Block Universe and realizing the script.

At 7:00am you're trying to decide to turn on the...