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 light bulb. But the Determinator already decided at 6:00am whether the light bulb would be on or off at 7:02am. Back at the dawn of time when Destiny wrote out the Block Universe, which was scripted before you started experiencing it...

This, perhaps, is the kind of unspoken, intuitive mental model that might lead people to talk about "determinism" implying that the future is determined before you make your decision.

Even without the concept of the Block Universe or timeless physics, this is probably what goes on when people start talking about "deterministic physics" in which "the whole course of history" was fixed at "the dawn of time" and therefore your choices have no effect on the "future".

As described in Timeless Causality, "cause" and "effect" are things we talk about by pointing to relations within the Block Universe. E.g., we might expect to see human colonies separated by an expanding cosmological horizon; we can expect to find correlation between two regions that communicate with a mutual point in the "past", but have no light-lines to any mutual points in their "future". But we wouldn't expect to find a human colony in a distant supercluster, having arrived from the other side of the universe; we should not find correlation between regions with a shared "future" but no shared "past". This is how we can experimentally observe the orientation of the Block Universe, the direction of the river that never flows.

If you are going to talk about causality at all—and personally, I think we should, because the universe doesn't make much sense without it—then causality applies to relations within the Block Universe, not outside it.

The Past is just there, and the Future is just there, but the relations between them have a certain kind of structure—whose ultimate nature, I do not conceive myself to understand—but which we do know a bit about mathematically; the structure is called "causality".

(I am not ruling out the possibility of causality that extends outside the Block Universe—say, some reason why the laws of physics are what they are. We can have timeless causal relations, remember? But the causal relations between, say, "dropping a glass" and "water spilling out", or between "deciding to do something" and "doing it", are causal relations embedded within the Block.)

One of the things we can do with graphical models of causality—networks of little directed arrows—is construe counterfactuals: Statements about "what would have happened if X had occurred, instead of Y".

These counterfactuals are untestable, unobservable, and do not actually exist anywhere that I've been able to find. Counterfactuals are not facts, unless you count them as mathematical properties of certain causal diagrams. We can define statistical properties we expect to see, given a causal hypothesis; but counterfactuals themselves are not observable. We cannot see what "would have happened, if I hadn't dropped the glass".

Nonetheless, if you draw the causal graph that the statistics force you to draw, within our Block Universe, and you construct the counterfactual, then you get statements like: "If I hadn't dropped the glass, the water wouldn't have spilled."

If your mind contains the causal model that has "Determinism" as the cause of both the "Past" and the "Future", then you will start saying things like, But it was determined before the dawn of time that the water would spill—so not dropping the glass would have made no difference. This would be the standard counterfactual, on the causal graph in which "Past" and "Future" are both children of some mutual ancestor, but have no connection between them.

And then there's the idea that, if you can predict the whole course of the universe by looking at the state at the beginning of time, the present must have no influence on the future...

Surely, if you can determine the Future just by looking at the Past, there's no need to look at the Present?

The problem with the right-side graph is twofold: First, it violates the beautiful locality of reality; we're supposing causal relations that go outside the immediate neighborhoods of space/time/configuration. And second, you can't compute the Future from the Past, except by also computing something that looks exactly like the Present; which computation just creates another copy of the Block Universe (if that statement even makes any sense), it does not affect any of the causal relations within it.

One must avoid mixing up timeless and timeful thinking. E.g., trying to have "Determinism" acting on things before they happen. Determinism is a timeless viewpoint, so it doesn't mix well with words like "before".

The same thing happens if you try to talk about how the Past at 6:30am determines the Future at 7:30am, and therefore, the state at 7:30am is already determined at 6:30am, so you can't control it at 7:00am, because it was determined at 6:30am earlier...

What is determined is a timeless mathematical structure whose interior includes 7:00am and 7:30am. That which you might be tempted to say "already exists" at 6:00am, does not exist before 7:00am, it is something whose existence includes the Now of 7:00am and the Now of 7:30am.

If you imagine a counterfactual surgery on the interior of the structure at 7:00am, then, according to the statistically correct way to draw the arrows of causality within the structure, the 7:30am part would be affected as well.

So it is exactly correct to say, on the one hand, "The whole future course of the universe was determined by its state at 6:30am this morning," and, on the other, "If I hadn't dropped the glass, the water wouldn't have spilled." In the former case you're talking about a mathematical object outside time; in the latter case you're talking about cause and effect inside the mathematical object. Part of what is determined is that dropping the glass in the Now of 7:00:00am, causes the water to spill in the Now of 7:00:01am.

And as pointed out in Thou Art Physics, you are inside that mathematical object too. So are your thoughts, emotions, morals, goals, beliefs, and all else that goes into the way you determine your decisions.

To say "the future is already written" is a fine example of mixed-up timeful and timeless thinking. The future is. It is not "already". What is it that writes the future? In the timeless causal relations, we do. That is what is written: that our choices control the future.

But how can you "control" something without changing it?

"Change" is a word that makes sense within time, and only within time. One observes a macroscopically persistent object, like, say, a lamp, and compares its state at 7:00am to its state at 7:02am. If the two states are different, then we say that "the lamp" changed over time.

In Timeless Physics, I observed that, while things can change from one time to another, a single moment of time is never observed to change:

At 7:00am, the lamp is off. At 7:01am, I flip the switch... At 7:02am, the lamp is fully bright. Between 7:00am and 7:02am, the lamp changed from OFF to ON.

But have you ever seen the future change from one time to another? Have you wandered by a lamp at exactly 7:02am, and seen that it is OFF; then, a bit later, looked in again on the "the lamp at exactly 7:02am", and discovered that it is now ON?

But if you have to change a single moment of time, in order to be said to "control" something, you really are hosed.

Forget this whole business of deterministic physics for a moment.

Let's say there was some way to change a single moment of time.

We would then need some kind of meta-time over which time could "change".

The lamp's state would need to change from "OFF at 7:02am at 3:00meta-am" to "ON at 7:02am at 3:01meta-am".

But wait! Have you ever seen a lamp change from OFF at 7:02am at 3:00meta-am, to ON at 7:02am at 3:00meta-am? No! A single instant of meta-time never changes, so you cannot change it, and you have no control.

Now we need meta-meta time.

So if we're going to keep our concepts of "cause" and "control" and "choose"—and to discard them would leave a heck of a lot observations unexplained—then we've got to figure out some way to define them within time, within that which is written, within the Block Universe, within... well... reality.

Control lets you change things from one time to another; you can turn on a lamp that was previously off. That's one kind of control, and a fine sort of control it is to have. But trying to pull this stunt on a single moment of time, is a type error.

If you isolate a subsystem of reality, like a rock rolling down hill, then you can mathematically define the future-in-isolation of that subsystem; you can take the subsystem in isolation, and compute what would happen to it if you did not act on it. In this case, what would happen is that the rock would reach the bottom of the hill. This future-in-isolation is not something that actually happens in the Block Universe; it is a computable property of the subsystem as it exists at some particular moment. If you reach in from outside the isolation, you can stop the rock from rolling. Now if you walk away, and again leave the system isolated, the future-in-isolation will be that the rock just stays there. But perhaps someone will reach in, and tip the rock over and start it rolling again. The hill is not really isolated—the universe is a continuous whole—but we can imagine what would happen if the hill were isolated. This is a "counterfactual", so called because they are not factual.

The future-in-isolation of a subsystem can change from one time to another, as the subsystem itself changes over time as the result of actions from outside. The future of the Grand System that includes everything, cannot change as the result of outside action.

People want to place themselves outside the System, see themselves separated from it by a Cartesian boundary. But even if free will could act outside physics to change the Block Universe, we would just have a Grand System that included free-will+physics and the future would be fully determined by that. If you have "freer will" we just have an Even Grander System, and so on.

It's hard to put yourself outside Reality. Whatever is, is real.

Control lets you determine single moments of time (though they do not change from one meta-time to another). You can change what would have happened, from one time to another. But you cannot change what does happen—just determine it. Control means that you are what writes the written future, according to the laws of causality as they exist within the writing.

Or maybe look at it this way: Pretend, for a moment, that naive views of free will were correct. The future "doesn't exist yet" and can be "changed". (Note: How are these two statements compatible?) Suppose that you exercise your "free will" at 6:30am to rescue three toddlers from a burning orphanage, changing their future from horrible flamey death at 7:00am, to happy gurgling contentment at 7:00am.

But now it is 7:30am, and I say:

"Aha! The past is fixed and can never be altered! So now you cannot ever have chosen any differently than you did choose. Furthermore, the actual outcome of your actions can never change either; the outcome is now fixed, so even if your past choice did now change, the past outcome wouldn't, because they are both just determined by "The Past". While your will was once free at 6:30am to change the future at 7:00am, it is now 7:30am and this freedom no longer exists. So now your will at 6:30am is no longer free. How can your past will have been free, now that there is only one past? Therefore I do not now assign you any moral credit for saving the orphanage; you no longer could have chosen differently from how you chose."

In the Block Universe, the "past" and the "future" are just perspectives, taken from some point within the Block. So, if the fixation of the past doesn't prevent the embedded decisions from having (had?) the property of freedom, why should the determination of the future prevent those embedded decisions from having the same property?

In the Block Universe, the Future is just like the Past: it contains the Nows of people making choices that determine their outcomes, which do not change from one meta-time to another.

And given the way we draw the causal arrows, it is correct to form the (un-observable) counterfactuals, "If I hadn't saved those children from the orphanage, they would be dead," and "If I don't think carefully, my thoughts will end up in Outer Mongolia." One is a counterfactual over the past, and one is a counterfactual over the future; but they are both as correct as a counter-factual can be.

The next step in analyzing the cognitive issues surrounding free will, is to take apart the word "could"—as in "I could have decided not to save the children from the orphanage." As always, I encourage the reader to try to get it in advance—this one is easier if you know a certain simple algorithm from Artificial Intelligence.

PPS: It all adds up to normality.

Part of The Quantum Physics Sequence

Next post: "The Failures of Eld Science"

Previous post: "Thou Art Physics"