Here’s how I think about it.

The universe is deterministic, and you have to grind through a deterministic algorithm in your brain in order to do anything.  And when you grind through that algorithm, it feels like wanting to do something, and intending to do it, and doing it, and being satisfied (or not). This is what it feels like to be the algorithm that steers us through the world.  You have the feeling that being in a deterministic universe, you should just do stuff, without needing to have effort or intention or desire. But that’s like imagining  you could digest food without secreting stomach juice.  Intention isn’t an extra thing on top of action, that could be dispensed with; having an intention is a part of the next-action-deciding algorithm.

So get out there and do stuff.

I don’t know if I’ve explained myself well; I might have just said the same thing three times.  What do you think?

I confess I dissolved the "free will" question for myself rather than about determinism/non-determinism, but I did think about determinism/nondeterminism in the course of it.

Basically, imagine you're designing a universe, what are the alternatives to determinism? Determinism and non-determinism both fully allow for free agency; whether who you are can be predicted effectively or not, and to what degree, meaningful states of the universe are caused by who you are.

The quickest alternative is stochastic; elements of the universe are random, to some degree, such that a perfect prediction is impossible not only by measurement but inherently. Here we've got the distinction between a highly complicated function and ... a highly complicated function that consults for input a series of dice rolls. There's potentially good functional reasons to include this if you happen to be designing a universe, but metaphysically, it doesn't feel much different from the perfectly predictable universe from the inside. The main advantage is we can imagine counterfactual universes exist or could have existed, depending how those dice rolls are implemented. However, it's arguable this is still deterministic - just with our universe spread out to predictable probability distributions rather than a more singular timeline. And to my understanding particles do act like this; which, speculatively, might be one of the more useful levels of physics to inject noise for diverse results. I think this could be meaningfully true, and give us a better universe than if it were not true, but it in no way dissolves nihilistic consideration.

Another alternative could be outside-view meddling: the universe itself is predictable, so you can see the whole thing/whole probability cloud of it, but if you aren't content with its outputs you can tweak something to adjust the whole state after (time of what was tweaked). The universe itself remains predictable, but from a timeless causal perspective is able to be altered by outside forces, whose determinism or lack thereof we can't guess much about directly because measuring outside space, time, and our local laws of physics is inherently challenging. In this case, the determinism of the superset of our universe and meddling forces depends on what the determinism-state of the outside meddlers is, which is unmeasurable to us currently (but might be communicated). Bargaining with these outside forces could be meaningful, but we have no way to tell, so it does not fully dissolve nihilism either.

Last alternative is things happen for no cause whatsoever, dice roll or otherwise. (Though we have reasonable evidence that things do happen for reasons also, so this is not the dominant influence.) Sometimes the universe just spawns events with no probability that can be calculated and they are incorporated. We should expect to see some form of fluctuations that continually defy attempts to fit sensible probability estimates to them as a category. This would not easily be part of a universe we could design ourselves, because implementing 'and things happen for no reason' contains an inherent paradox; the feature inherently has to exist without implementation. This does not exactly dissolve the nihilistic perspective to me, either.

Essentially, I do not think nihilism as a perspective can be dissolved either by determinism or by a lack of determinism. The question of meaning is orthogonal to whether we are implemented predictably or unpredictably.

If we go back to theology, for a moment: Some wrestled with this, in the form of predestination. If whether you will "go to Heaven" (insert equivalent desired universe state) is predetermined, does it matter which action you take? And the answer they came up with was yes: it matters, because how you act now reflects what state you are predestined for. Just because someone can in theory step out of time and "see" where you wound up 20 years from now, you don't get there without having actively taken every causal step on the way to that 20 years from now. If the future of the universe can be predicted from the current state - act so that the state you are predicting is the desired one.

Why bother with effort and hardship if, at the end of the day, I will always do the one and only thing I was predetermined to do anyway?

Say we plug in a specific example here: "Why bother making breakfast if, at the end of the day, I will always do the one and only thing I was predetermined to do anyway?" Answers may vary, but I imagine most will boil down to 'Well if I don't I'll be hungry/tired/unpleasant feeling, and the effort it takes to make breakfast is worth avoiding those feelings' or the inverse "If I do make breakfast I'll be full/energized/pleasant feeling..". This question has different answers based on what action we fill in, but all of them rely on what you value/desire to be answered. Motivation generally comes from the expected or desired outcome of an action.

It seems like your issue may not be determinism taking away your drive/'responsibility' to do something, but rather your comfort/complacency with the current state of your reality, similar to the senioritis a student may experience. If the only reason a student is studying in class is to get an adequate GPA, once they've learned enough to acquire that GPA, there isn't any reason for them to continue as their goal has been met. Conversely, a student who is pationate about a subject isn't motivated by an external stimulus (GPA), but rather intrinsic motivation (their desire to learn more).

I'd recommend reading So8res' sequence on Replacing Guilt, but if you don't have that kind of time You're allowed to fight for something and Half-assing it with everything you've got were the two articles that hit home and helped me break out of a similar mindset of pointlessness by revealing that there are things I care about/worth the effort.

Here's why determinism doesn't bother me. I hope I get it across.

Deterministic systems still have to be simulated to find out what happens. Take cellular automata, such as Conway's Game of Life or Wolfram's Rule 110, . The result of all future steps is determined by the initial state, but we can't practically "skip ahead" because of what Wolfram calls 'computational irreducibility': despite the simplicity of the underlying program, there's no way to reduce the output to a calculation that's much cheaper than just simulating the whole thing. Same with a mathematical structure like the Mandelbrot Set: its appearance is completely determined by the function, and yet we couldn't predict what we'd see until we computed it. In fact all math is like this.

What I'm getting at is that all mathematical truths are predetermined, and yet I doubt this gives you a sense that being a mathematician is pointless, because obviously these truths have to be discovered. As with the universe: the future is determined, and yet we, or even a hypothetical outsider with a massive computer, have to discover it.

Our position is better than that, though: we're not just looking at the structure of the universe from the outside, we're within it. We're part of what determines the future: it's impossible to calculate everything that happens in the future without calculating everything we humans do. The universe is determined by the process, and the process is us. Hence, our choices determine the future.

When you despair about determinism, you imagine a future that is determined regardless of your actions, but it's actually a future that is determined through your actions (and the actions of everyone else).

If the future was determined regardless of your actions (e.g. through fate), then of course your actions would be meaningless. You might instead enjoy the day. Actually, not even that, because whether you enjoy the day would also be determined regardless of your actions. So it's not really a coherent worldview, because you clearly do some things based on your decisions -- for example you decided to ask this question on LW.

So, I suspect that what you currently believe is an incoherent perspective, where you feel like you can make trivial decisions (such as whether to ask people on Reddit and LW), and it's just the big decisions (what will happen to you in 5 years, or the future of human civilization) that are determined by fate and somehow causally isolated from your trivial decisions.

And that is a natural mistake to make. For example, people who deny evolution sometimes admit that yes, mutations can cause trivial changes (such as a species of beetle changing its color), but those can never accumulate to big changes (such as fish evolving to reptiles), because... well, intuitively, some big things just seem too big to be composed of little things, no matter how many little things we add together. A mountain cannot be built from atoms, that's just silly; no matter how many atoms you join together, the result is still something you can only see using a microscope!

Also, in quantum physics, ten or hundred particles can be in a superposition, but it would of course be silly to imagine that entire humans or planets or universes could be in a superposition. That's silly; no matter how many particles you put together, the result is never a macroscopic object!

And just like that, no matter what control you have over the trivial decisions, such as whether to move your hand, whether to say or write some word, it may feel like this all will somehow cancel out, and won't make a change in what happens to you in 5 years.

(Just speculating here. Maybe this is not your model at all.)

But if there is no natural boundary between the "small" and "big" things, then the big things can change, as a result of many small changes pushing in a similar direction.

*

The way I solve it, is that I see this as two separate perspectives, "in universe" and "out universe". In-universe, I make choices, and things happen as a result of my (and everyone else's) choices. Out-universe, everything is predetermined; in the sense that if some alien recorded a big movie of our universe and played that movie again, the same things would happen again. From the alien's perspective, when the movie is played again, the people in the movie are utterly predictable, even if from their own perspective they think and make choices. Nonetheless, without their thoughts and choices, the movie could not exist. And I am not the alien; I am one of those people inside the movie.

Basically, it is a logical mistake to mix the in-universe and out-universe perspectives. Things that make sense out-universe, for example playing the movie again or playing it in reverse, do not make sense in-universe, how the people actually experience it.

All of these responses are faith-based arguments in the guise of rational explanation. At the same time though, they all demonstrate a healthy mindset that is indeed the most rational one to hold given the information at our disposal RIGHT NOW. Forecasting into the future, when all of the aforementioned unknowns and randomness inevitably become known and predictable, is when believing in determinism can lead one down a dark path. I empathize with your perspective and have dealt with these thoughts and feelings myself. In the end, it comes down to being able to train yourself to purposefully pick and choose the aspects of life you choose to judge with fierce rationality and the aspects in which you allow a little leeway... or maybe just tweaking your definition of rationality as a whole to maximize long-term happiness.

The tool you essentially have in the face of determinism despair is awareness of distributed causality. It is the 'thinking about/sense of' part that is (or seems to be) causing it. A practical exercise I like is asking "If I had to bring myself to face the most 'makes me feel bad about myself' cause of my demotivation, what would it be?". Existential despair often masks some other pertinent but deeply invalidating anxiety.

Why bother with effort and hardship if, at the end of the day, I will always do the one and only thing I was predetermined to do anyway?

You are imagining yourself as a free spirit imprisoned in a deterministic machine, but if "everything that will happen throughout the lifetime of the universe was predetermined at the beginning of the universe", then you were also predetermined to resolutely plough through the effort and hardship (if you do). Everything still adds up to normality.

We speak of a self-driving car as interpreting and making decisions about what it sees in front of it and how to deal with it, despite it being a designed machine. Why suppose that human drivers are doing anything less?

"Why bother with effort and hardship if, at the end of the day, I will always do the one and only thing I was predetermined to do anyway?"

I think this is kind of muddled thinking. You will either bother with the effort and hardship or you will not bother and will loose out on the potential rewards of that effort. Before you ever heard of determinism how did you deal with this situation? I assume you assessed the potential rewards, risks and how much effort the action would cost, and then decided if you thought it was worth it or not.

Now that you think the world is deterministic, I don't see what changes. You still have to make a choice about how much effort to exert, or hardship to endure, in pursuit of any given goal. Yes, in a deterministic universe the eventual outcome is predetermined, but for most things you are considering it is predetermined not in spite of your choices, but because of them.

Lets say you were thinking of writing a book, and lets say that if you wrote this book, it could be successful. There are three possible worlds, we don't know which we live in:

1. Writes book > it is successful.
2. Writes book > not successful.
3. Does not write book.

When we compare 1 and 2, it just says that any risky endeavour can go wrong for reasons beyond our own control. Whether we are at the mercy of chance, or determinism, doesn't change this situation in the slightest. In either case we would have to try and guess at the chances of outcome 1 and 2 and proceed according to the chance we deem acceptable.

Now, compare 1 and 3. This is (I think) where you issue is. You feel like determinism somehow has you trapped in timeline 3, when you want to be in timeline 1. You want to motivate yourself to do things (in this example, to write) to move yourself from timeline 3 to 1. But, when you try and summon up the motivation you feel like the book or whatever will be doomed to not being successful, because of this determinism. But, that is not at all how it works. Lets say that the book would be successful if it were written, then the existence (or not) of a successful book is causally "downstream" of your choice to write it or not. In graph form

Determinism > Your Decision > Success.

In this example, your decision "screens off", determinism. In the domino-chain of cause and effect your choice about whether to do something or not is a vital point, perhaps the only vital point, in the success of your plans.

To put it in another way, look at a counterfactual like "if X was different, Y would be different". Counterfactuals can still be true in a deterministic world. (In fact, determinism probably helps counterfactuals be true). Counterfactuals are the core of cause and effect. We can 100% believe that if you try you will succeed, while simultaneously believing that whether or not you try follows from a deterministic decision making process.

If none of this helps, I would weirdly advocate looking at the Christian idea of the "Elect of God". This is the idea that God has already predestined the entirety of history, including the good and bad deeds of all individual humans, and hence whether those humans will go to heaven or not. The "Elect of God" are the people god has predestined for good deeds, and therefore for heaven. 

Note again, the causal structure is: [predestination > good deeds > heaven],   and not    [predestination > heaven] with [good deeds] irrelevant. If you take out the good deeds the sequence no longer works. Just like if you had  [Gun fires > bullet flies > bird dies] it is true to say the gun shot killed the bird, but it is also true to say that without the bullet the gunshot would not have killed the bird. As I understand it your case is  [Atoms and stuff jumbling through space > my brain makes a decision > an outcome occurs], which has the same structure. Maybe the ultimate cause was the atom jumble, but it had to go through you, and it remains counter-factually true that if you had made a different decision a different outcome would have followed.

Start here?

It seems that you didn't properly integrate determinism on the emotional level and that's the source of your feelings. 

Do you share an intuition that if determinism is false then it means that reality is separated into two things: 

1. You and stuff that you directly control via choices
2. Everything else that is some mechanism that is just doing it's thing and is beyond your control

And, if determinism is true, then it means that there is no 1 only 2?

Current science is based on models that are from any agent point of view non-deterministic, and philosophy doesn't make any predictions.

That aside, there is still a strong sense in which determinism is in practice useless, even if the universe truly was deterministic. You don't know the initial conditions, you don't know the true evolution rules, and you don't know and can't predict the future outcomes any better than alternative models in which you don't assume that the universe is deterministic.

For example: standard quantum mechanics (depending upon interpretation) says either that the universe is deterministic and "you" is actually a mixture of infinitely many different states, or non-deterministic, and it makes no difference which way you interpret it. There is no experiment you can conduct to find out which one is "actually true". They're 100% mathematically equivalent.

However: neither option tells you that there is only one predetermined outcome that will happen. They just differ on whether the incorrect part is "only one" or "predetermined". Neither are philosophical determinism, even if one interpretation yields a technical sort of state space determinism when viewed over the whole universe.

However, I can't offer much help with the actual problem in your post - that you need to avoid thinking about determinism to avoid being demotivated. I just don't feel that, and can't really imagine how thinking about determinism would make a difference. If I consider doing something, and have the thought "a superintelligent being with perfect knowledge of the universe could have predicted that I would do that", it has no emotional effect on me that I can discern, and doesn't affect which things I choose to do or not do.

As a fellow incompabitilist, I've always thought of it this way:

There are two possibilities: you have free will, or you don't. If you do, then you should exercise your free will in the direction of believing, or at least acting on the assumption, that you have it. If you don't, then you have no choice in the matter. So there's no scenario in which it makes sense to choose to disbelieve in free will.

That might sound glib, but I mean it sincerely and I think it is sound. 

It does require you to reject the notion that libertarian free will is an inherently incoherent concept, as some people argue. I've never found those arguments very convincing, and from what you've written it doesn't sound like you do either. In any case, you only need to have some doubt about their correctness, which you should on grounds of epistemic humility alone.

(Technically you only need >0 credence in the existence of free will for the argument to go through, but of course it helps psychologically if you think the chance is non-trivial. To me, the inexplicable existence of qualia is a handy reminder that the world is fundamentally mysterious and the most confidently reductive worldviews always turn out to be ignoring something important or defining it out of existence.)

To link this more directly to your question --

Why bother with effort and hardship if, at the end of the day, I will always do the one and only thing I was predetermined to do anyway?

-- it's a mistake to treat the effort and hardship as optional and your action at the end of the day as inevitable. If you have a choice whether to bother with the effort and hardship, it isn't futile. (At least not due to hard determinism; obviously it could be a waste of time for other reasons!)

Have you read https://www.lesswrong.com/posts/NEeW7eSXThPz7o4Ne/thou-art-physics ?

I've skimmed the answers so far and I don't think I'm repeating things that have already been said, but please feel free to let me know if I am and skip re-reading.

> What I know about science and philosophy suggests that determinism is probably true

What I know about science and philosophy suggests we shouldn't be really sure that the understanding we believe to be accurate now won't be overturned later. There are problems with our physics sufficient to potentially require a full paradigm shift to something else, as yet unknown. So if "determinism is true" is demotivating for you, then consider adding a "according to my current understanding" and a "but that may be incorrect" to that statement.

I also read in some of the discussion below that determinism isn't always demotivating for you - only in some cases, like when the task is hard and the reward, if any, is temporally distant. So I wonder how much determinism is a cause of your demotivation, rather than a rationalization of demotivation whose main cause is something else. If someone convinced you that determinism was false, how much more motivated do you expect you would be, to do hard things with long delays before reward? If the answer comes back "determinism is a minor factor" then focusing on the major factors will get you most of the way to where you want to be.

But, suppose determinism is definitely true, and is, on further reflection, confirmed as a major cause of your demotivation. What then?

This has actually been said in a few different ways below, but I'm going to try and rephrase. It's a matter of perspective. Let me give you a different example of something with a similar structure, that I have at times found demotivating. It is basically the case, as far as I understand, that slightly changing the timing of when people have sex with each other will mean a different sperm fertilizes a given egg, and so our actions, by for example by accidentally causing someone to pause while walking, ripple out and change the people who would otherwise have been born a generation hence, in very unpredictable ways whose effects probably dominate the fact that I might have been trying to be nice by opening a door for someone. It was nice of me to open the door, but whether changing the set of which billions of people will be born is a net good or a net bad, is not something I can know.

One response to this is something like "focus on your circle of control - the consequences you can't control and predict aren't your responsibility, but slamming the door in someone's face would be bad even if the net effect including all the consequences that are unknowable to you could be either very good or very bad".

This is similar in structure to the determinism problem - the universe might be deterministic, but even if so, you don't and can't know what the determined state at each point in time is. Within your circle of control as an incredibly cognitively limited tiny part of the universe, is only to make what feels like a choice to you, about whether to hold a door open for someone or slam it in their face. From your perspective as a cognitively-bounded agent with the appearance of choice, making a choice makes sense. Don't try to take on the perspective of a cognitively-unbounded non-agent looking at the full state of the universe at all points in time from the outside and going "yep, no choices exist here" - you don't have the cognitive capacity to model such a being correctly, and letting how such a being might feel if it had feelings influence how you feel is a mistake. In my opinion, anyway.

Why is it demotivating? 

I've never believed in the concept of free will, ever. So when I matured and started seeing that everyone takes it for granted, I was more shocked than anything. We can just like... decide to do things for ourselves? That sounds utterly ridiculous to me. Everything is a dominoe effect from something that happened prior. Everything is influenced by your parents, upbringing, genetics etc. Nothing is ever decided by you, and the belief that it is, is a symptom of human egoism. 

Again I ask, why is that demotivating? Perhaps it's my world view, and that I genuinely can't conceive of what it feels like to decide something for yourself. To me, this is freeing, if I do something - it's not my fault. It's the natural consequence of something that came before. Everything that happens is like wind hitting the sails of the boat. There's no need to stress because no matter what I do, it's all accounted for --- all predetermined. 

Does that make life meaningless? Why? You still feel dopamine going off in your brain don't you? What difference does it make that you weren't the one to make it happen?

Here's how I think about it.

Whether or not the world is deterministic, we still live with a single, deterministic history, and we don't know what history we'll be in until we already have lived it. We also live the computation of events as they happen. We don't get to choose where we end up, but we also can't know where we will end up because we are the computation happening that creates the single, fixed past we know about.

Demotivation about determinism happens because you thought you had a choice and now you're bummed that you don't. But if you realize that you never had a choice, you can't be demotivated because that's just how things are and demotivation requires some gap between expectation and reality.

Feeling a lost sense of purpose or motivation is normal upon realizing that we can't control the past, don't know the future, and can't know in full how we come to live in that fixed history. It's also a phase you have to go through, and out the other side is acceptance that the world works as it does because you had already been living it, and the demotivation will evaporate because the disappointment at not having free will goes away.

My answer has two parts.

On one hand, I prefer an agnostic position (that is, there is a multiverse of possible realities, some might be deterministic, and some might be non-deterministic, and I don't really know which of the realities I am in (or even if one can sometimes "migrate" between the realities, so these "implicit hidden fundamental properties" of the reality being deterministic/non-deterministic underneath might change through subjective time)). So if there is some aspect of demotivation here I am really struggling about myself, that would be how difficult it is to make real tangible scientific and philosophical progress towards better understanding the world I am in.

On other hand, when I really imagine the world being deterministic, I remind myself that my current state of elation/desperation/boredom/excitement/demotivation/being highly driven, myself currently writing this comment, and so on, is predetermined (under this assumption). The resulting reflection has interesting effects and changes my inner state quite a bit... It feels almost like a meditation-induced insight sometimes...

In some sense, my insufficient ability to believe in determinism is what interferes with my ability to have those nice meditation-like insights which change my inner state so much...

Let's say the entire biography of the universe has already been written. An unending, near infinitely granular chain of cause and effect, extending forward in a single direction: time. For a model of this, you could use boxes representing choices (we'll get to that later) and potentially multiple (again, later) arrows between boxes in such a way that an arrow from A to B means A is the cause of B, plus an axiom that there is no way to go back, meaning if there is a path from A to B there is not a path from B to A. (This is pretty much the definition of a branch in a directed tree). 

If you, from any given branch, trace human life, your grandmas 20-25 years, Saturn from 1720 to 1963, etc... you should get roughly the same thing: A to B to C to D........ to wherever you choose to stop counting. A single one width arrow in which every cause has a single effect, and viceversa, and everything that happened was originally intended to.

You can definitely see it that way, but its not very interesting. 

A good idea might be to consider the fact that, with the intuition and evidences we have, there is not really a way to tell whether the branch we're living in, in which every event has either 0 or 1 (this is a huge abuse of the term, but I'm speaking to intuition) probability, since it will either happen or not (again, this is not true but bear with me), is unique, or determined, if you know the whole structure of the tree.  

With that in mind, things improve a bit. Sure, you are always going to live a single A to B to C succession of events, but you don't know which. Seems trivial, and it is. And yet, it solves a lot of problems. See asimetric information and incomplete information games if you are interested in that idea. 

My point is that, while choice is problematic when everything is said and done, it might very well be useful when you are still in the thick of it. Say that you are in a branch which opens alternatives B and C. The B-you , when laying in their deathbed surrounded by their B-grandchildren might say "everything was predetermined, B was written all along, etc". But there is an equally compelling argument from the C-you, with their C-Grandchildren in their C-deathbed. Both are right in this model, in the sense that everything was written beforehand, but you could loosely define choice between B and C as deciding which do you want to live in. The fact that you are inhabiting C, for instance, doesn't negate the existence of B. 

The main takeaway here is that, if the deterministic model is huge enough, the concept of choice lies in the uncertainty of the position you ocupy within it.  This is not a perfect explanation, but it served me to soothe the existential dreads.