Juan F. Meleiro

No final do seriado Watchmen (2019), Dr. Manhattan se deixa capturar. Alega que o futuro já está definido, e essa luta está perdida. No entanto, um futuro onde a batalha é ganha também é consistente com os fatos conhecidos. Isso nos leva a concluir que 1) Dr. Manhattan não tem livre arbítrio /porque/ é omnisciente e vive num mundo deterministico; e 2) algum processo externo deve decidir qual dentre os futuros plausíveis é o que ocorre – a história do mundo é pré-determinada.

SPOILERS FOR Watchmen (2019)

The Fate of Dr. Manhattan

At the end of Watchmen (2019) [1], Dr. Manhattan is captured. This is unsettling, as Dr. Manhattan is supposed to be omniscient – which means he should have foreseen it. Seems like an inconsistency in the series logic.

What bothered me is not a potential narrative flaw – those abound, anyway. What bothered me is that it *wasn't* inconsistent. At least if we believe the world is deterministic. Indeed, I think the logical conclusion coming from the facts is that Dr. Manhattan cannot possibly believe he has free-will.

Let's unpack that.

We need to clarify some things. First, what is determinism; second, what is a sentient being; third, what is an *omniscient* being. Of course, we ain't going to even come close to seriously systematize such topics, but we can have fun.

In a deterministic world, by definition, the future history of the world is determined by its current state (be that the position and momentum of every particles, the universal wave function, whatever). In that setting, what should a sentient being be? Apart from matters of self-counsciousness, the Hard Problem, other matters of the mind, let's focus on the idea that sentient beings are

That is, there are some subsystems of the world that are capable of information-processing, hold some (potentially) imperfect model of the world, and act according to some goals, planning ( course-correcting; whatever) bound by that model.

This is quite general. Indeed, sentient beings (in our sense) can vary in at least two conceptual spaces: computational power and the quality of their models. We don't really care about computational power (as we'll see) – just assume the beings in question are powerful enough to perform the tasks they could perform, other factors nonwithstanding.

The interesting bit – and where we'll characterize omniscience – is the quality of the model. Obviously, if we are to avoid coming close to paradoxes, any model of the universe which is a *part* of the universe cannot be complete and correct. But we needn't come to such extremes to characterize some types of omniscience. Let's just assume models are somewhat correct; just enough so that beings are competent enough to say they indeed have a model of the world.

Let's say a *time omniscient* being is one whose model contains somewhat precise informations about all times in which it exists, including, at a certain time, about the future. This is part of what Dr. Manhattan is capable of. On the other hand, he's also *space omniscient*: aware of facts spatially removed from him. Let's stay clear of relativity, though.

So, here's the question: is it possible for a sufficiently competent time-omniscient sentient being ever *loose* – that is, *not* meet its goals (supposedly, because of some form of antagonism from the external world)?

I think so.

Think about it: given the long-past history of the world, even before the existence of such being, the whole history of the world is determined, and that begin couldn't possibly influence that [3].

Now, an important point: I believe other, non-omniscient beings do have free-will *even* in a deterministic world. I'll write about it some other time – for now, I ask you to grant me that premise. If that's not true, it doesn't invalidate my argument, but makes it redundant.

So, when the time-omniscient being comes into existence, they'll be aware of their whole future. If they reach their goals not is entirely determined, and they know it. They might ponder their possible courses of action (indeed, they might have no other option but to do it).



[3]: This raises other questions, about, e.g., the possibility of omnipotent beings. Leave it to another time.