I'm a very logical person. I like mathematics, software engineering, physics... everything in that area. Also I'm an anti-theist.

My understanding of the universe:

If you would take every atom (as in the smallest particle) in our universe plus whatever there is beyond and all the movements of these particles in every dimension and copy & paste it somewhere else (like to an other dictionary on your computer) then in both universes the same actions will take place. The stars will make the same movements and humans will make the same thoughts.

If that is true, someone with unlimited mathematical power and knowledge could calculate what will happen in the future.

Is there any sound and logical argument against determinism? Any great philosophers who defended indeterminism?


This (copying of the universe and calculating the future) is all hypothetical. It doesn't matter where you put the copy or how you would calculate it. It only shows that if you would do it, you could in fact predict the future --> determinism.

I take it that so called 'random' events (eg. Heisenberg's Uncertainty Principle) are just not understood by human beings because we aren't capable of understanding it. I just wanted to demonstrate why I think we live in a deterministic word.

  • 6
    "If that is true, someone with unlimited mathematical power and knowledge could calculate what will happen in the future." - not necessarily, because computation takes time. The computation may take longer than the actual events to happen.
    – user2953
    Commented Jan 29, 2015 at 15:07
  • @Keelan i dont think its possible to have unlimited mathematical power. but lets say that if someone had it, they dont need any computation time ;-)
    – yamm
    Commented Jan 29, 2015 at 15:11
  • 1
    If they have unlimited mathematical power, enough to precisely model every relevant element of the universe, they are no longer modelling; they have created another identical universe, and are watching it play out. Commented Jan 29, 2015 at 19:34
  • 1
    @YannikAmmann, not being a practitioner in quantum computation, I don't know for certain, but the way I learned it in grad school, resolving a qubit in supposition is a truly random event, and therefore unlike a coin toss in which it could theoretically be calculated if you knew the forces pushing on the coin. I agree though, that determinism in the philosophical sense is easier to argue (even if I disagree with it). Commented Feb 12, 2015 at 18:07
  • 2
    towards the virtue of obtaining knowledge (i.e. philosophy), I suggest you review Bell's theorem: plato.stanford.edu/entries/bell-theorem/#7
    – MmmHmm
    Commented Jun 28, 2018 at 2:18

19 Answers 19


I would highly recommend learning QM (Quantum Mechanics). QM is science's strongest current theory for "how the universe works," and it has very interesting things to say about determinism. It will be very hard to debate determinism vs. indeterminism without catching up on several decades of QM.

(This is a ridiculously high level view of QM. I give this disclaimer because I am sure my natural English approach has technical inaccuracies. I recommend learning the math from a professional teacher to correct any misconceptions I may cause.)

QM models everything as a "waveform," which is nice and clean for individual particles, but gets messy quickly as the particles interact. It turns out that its very hard to measure the waveform; the mere act of measuring it changes its state. The fundamental limit of "classical" measurement is the uncertainty principle.

Consider this thought experiment: Pluck a string in a dark room. Take a flash picture of it, and develop that picture. You will see the string in some bent shape... whatever position it happened to be in when the flash went off. You cannot simultaneously measure its amplitude and its phase. It could be at a low amplitude, but at 90degrees, where the string is as outstretched as it will get. Or it could be a very high amplitude, but at a much lower phase angle, where the string has a velocity.

Now if we wanted to get more information, we could take a second picture, and do some math to determine how the string had to vibrate to satisfy both pictures. We could even take 4 or 5 pictures and get an even more confident answer, watching the string vibrate. We could eventually measure both the amplitude of the wave, and its phase. Then we could do all sorts of cool things. Radar is built on this principle.

At the quantum level, things get hairy. Consider photographing a string so tiny that the mere energy of the strobe disrupts its motion, like a gust of wind blowing out a candleflame. This is going to be harder. Each time we photograph the string, we disrupt it enough that the information in the photograph ceases to be very helpful. When we take multiple photos, we find each additional photo is not adding any more information! (As for why this happens, learn the real math. It's not just an empty claim; it is a well recognized effect of QM that frustrated many a deterministic scientist!)

What if we turned the strobe down? What if we made it weaker so that it doesn't knock the string around so much? What if we just had a quiet lamp generating light in the corner? Now we wouldn't disrupt the string, but we need a much larger exposure time to get some information. As a result, we can easily see the amplitude, but we lost track of the phase, as it blurred together.

This is the Heisenberg uncertainty principle there is a limit to how much you can know both the position and velocity of an object. The strobe version could give position, but not velocity. The bulb version could give velocity, but poor position information. There are an endless set of options in between, but none of them violate a fundamental limit. (This is not just abstract philosophy. These results have been observed many times, and are highly accredited).

So, back to our problem of determinism. QM does not actually defend nor refute determinism. However, it does have some harsh things to say about its limitations. These arguments are known as "interpretations," because none of them refute the other. They just look at the problem in different ways. We'll start with your least favorite, and move towards what I believe will be your favorite.

  • Indeterminism One perfectly valid way to interpret the results of decades of QM experiments is to argue that there are, at a fundamental level, some events which are completely indeterminate. At each of these events, the universe rolls a statistically perfect die, and determines the outcome. This is not a mere "coin toss," where the physics suggest an outcome. In this case, the physics literally suggests there is no known way to predict the outcome. Nothing in QM refutes this position. In fact, in my opinion, it happens to be the easiest position from which to start to understand QM.

  • Many Worlds Another perfectly valid way to interpret the results is to argue that, at each classical "event," two universes are created. In one, the event occurred. In another, the event did not. This brings in the determinism you are looking for, but at a cost: we cannot currently observe any of the nearby worlds that are on "almost identical" paths. There is simply no known physical or mathematical solution to "jump" between worlds.

  • Unmeasurability QM does allow a single universe with determinism, as you desire. However, it comes with a catch worthy of a genie in a bottle: you can't measure it. In theory, for every particle which has a value we can measure, we can think of it as being a particle with two values: an amplitude and a phase. If we were to be able to know both amplitude and phase, we could build your computer and start predicting the future. The catch is: we can't. By the rules predicted by countless myriad experiments, there is simply no way to classically measure both amplitude and phase of a value simultaneously. There are these cool things called "weak measurements" and "entanglements" which do really neat things to measure both amplitude and phase simultaneously, but even they cannot truly break free of this limit. Those cool structures like "entangled photons" have an Achilles heel: while you can be confident that both particles have the same amplitude and phase, observing it does dirty things to the link, preventing you from actually getting classical readings.

So there are three views on QM. QM does not refute determinism, but it doesn't prove it either. It does state that any deterministic view of the universe must hold to very strict rules, or it will be inconsistent with the observed scientific results of QM.

And to think: that was just discussing the idea of whether an electron has "freewill." Now imagine how much fun the discussion is for freewill of a person. Like with QM, it is totally possible for determinism and indeterminism to be consistent. All it takes is a few careful shifts of definition.

  • 1
    As a follow up topic, consider exploring the definition of "computability." You'll find that, even with all the information, the universe is still not "computable" because our current definition of computation is only over the set of integers, not the real numbers. We can approximate real numbers with floating point values, but they are not real numbers. QM results strongly suggest that the world is based on real numbers, not integers.
    – Cort Ammon
    Commented Feb 23, 2015 at 15:54
  • 1
    @YannikAmmann I think you could make a fair argument that it is the alchemy of the modern age. However, you have to recognize that they do a far better job predicting the results of real life experiments than anything we've come up with. My personal favorite "rabbit hole" is the journey from the double-slit experiment (classical wave mechanics), to single-photon-double-slit (Poorly described by classical mechanics), onwards towards the eraser and the delayed eraser. At some point along the way, you should call BS, only to find it is an easily repeatable experiment done hundreds of times.
    – Cort Ammon
    Commented Feb 25, 2015 at 16:58
  • 2
    @mart The full version of what I think I was taught is that everything is described by a wave function. The values describing this wave function for a given frequency can be seen as a complex value describing its amplitude and phase. For the Heisenburg uncertainty, there are transforms which define "position" and "momentum" in terms of amplitude and phases of waves. However, it turns out that we know of no method of observing these values directly. We can only classically observe a coupling of position and momentum (such as measuring the "real portion of the complex value").
    – Cort Ammon
    Commented Feb 25, 2015 at 21:27
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    To do a "classical" observation, one does a quantum interaction with the system under test, and then operates in a way which reinforces the portion of the interaction we are interested in seeing. The operations we have to reinforce this operation demonstrate the limits we see in the answer you linked. However, there is no way to extract just the state of the particle. You can only extract information about the combined system after the interaction. You added information into the system in the form of the probing particles. They had momentum and phase.
    – Cort Ammon
    Commented Feb 25, 2015 at 21:29
  • 1
    You can eventually grow the system to be big enough where you can reliably measure the position and phase of the system. However, the effect of the original particle becomes swamped by the effect of all of the noise of the non-coherent parts of your test setup "entering" the system in an uknown phase. If you could perfectly measure the position and momentum of one particle, you could use it to perfectly measure another, but you can never measure the first particle in the first place!
    – Cort Ammon
    Commented Feb 25, 2015 at 21:31

Daniel Dennett has nicely provided answers to the question of determinism. He claims that determinism and inderterminism are not incompatible. Fundamentally, we cannot definitively answer the question, nor does it make a difference if things are determined or not. Either way, we are morally obligated.

Nevertheless, your logic for a deterministic universe is problematic. You say that a copy has the same rules as what it is copied from, therefore because the rules do not change the universe is determined. I don't see the logic? Football has the same rules copied from one game to the next, but each game is different and prior to the end, the outcome is unknown. The same rules mean that the constraints are the same, but it doesn't delineate all the opportunities or determine how the rules are used.

Is a mathematical function for social relations obtainable? The very probability that math is correct hinges on the fact that some things are impossible to prove (Gödel's incompletness theorem), thus an all knowing mathematical genius would be unable to predict the future with math. If she knew everything about math (the ability to prove it all), math would be a contradiction and not useful for prediction. If she didn't know everything in math (couldn't prove it all) she would also not be all knowing, and would again be unable to predict the future. There cannot be a being with predictive mathematical determinism. A paradox like you posed points out that such a being cannot exist (for other examples of paradoxes that illustrate that something is false see the village barber paradox).

  • Your logic seems,'because I can make an exact copy the original is deterministic'. You made a copy, and within the universe you copied there is likely to be randomness and agency (as you said 'whatever is beyond' is copied). It is impossible to prove that there is not one or the other. As such both universes will contain randomness and agency that make them different and unpredictable.
    – alfonso
    Commented Jan 30, 2015 at 18:28
  • You're wrong about mathematics. Mathematics does not depend on statements that are independent from the chosen theory such as CH is independent of ZFC. Also, the barber paradox has nothing to do with a being with predictive mathematical determinism, whatever you mean by that. It just means that no such barber can exist. That's all!
    – user21820
    Commented May 12, 2015 at 8:15

Here is another argument against determinism which I have just stumbled upon in a youtube video by Derek Muller:

well let's assume for second that Laplace was right and that knowing the state of the Universe any one time means you also know its state at every other time as well; well, that would mean that the information in our universe would be constant; but if information is entropy that would mean the entropy of the universe is also constant, and that does not appear to be the universe that we live in; the second law of thermodynamics states that entropy in the universe increases with time.

The quote is from the 5m54s mark of the video, but the argument is built gradually from the beginning of the video, and I advise watching it before passing judgement.

In my opinion he goes off the rails when he starts talking about free will at the end of the video; so I would love to hear from commentators how accepted is the physical part of the video about theory of information, indeterminism, quantum mechanics, and thermodynamics; in particular, since last I was aware of it, whether the universe is deterministic or indeterministic was an open question, reason dictates that there is probably a problem in his argument.

Note that the video description lists several professors including Michio Kaku as having given advice in the making of the video.

  • Just because something is more chaotic does not impede the potential for order (see international relations theory). Thus, entropy alone does not inherently limit our ability to predict. However, Chaos Theory would argue oppositely, and perhaps something what you, nir, are getting at. While an effect is deterministic, diverging outcomes are possible and prediction is not necessarily predictable.
    – alfonso
    Commented May 13, 2015 at 16:29
  • 1
    a) this is not my argument, b) I do not understand your comment.
    – nir
    Commented May 13, 2015 at 19:00
  • There are different uses of information in physics, because it means resolution of uncertainty. Thermodynamic information is defined as the inverse of entropy: ordered-state information is 'lost' to disordered thermal states which we cannot extract work from. But, the record of what happened such that in principle you could work out the state of the system is still there - this relates to en.wikipedia.org/wiki/No-hiding_theorem & the proposed law of conservation of quantum information. It spreads out, rather than being lost, generally. Entropy is, a complex topic
    – CriglCragl
    Commented Dec 10, 2020 at 19:21

I rephrase your question.

I'm an atheist, but just suppose you have someone with the god-like power to copy and paste the universe. Then at least the godlike thing doing the copying and pasting could see that the universe is, in fact, deterministic. Aint I right?

The thing is, outside your thought experiment it does not matter all that much. Who cares if the universe is deterministic but complex enough that we just can't ever know what the weather will be like in three weeks or when an earthquake strikes, or if it's indeterministic and we thusly can't ever know what happens next.

Also, as other answers pointed out, QM seems to point out that there's always randomness. If my understaning is correct, the Heisenberg uncertainty principle not only says that you can't observe speed and momentum at the same time to arbitrary exactness, but that those two properties are never there in an arbitrarily exact way in the first place. So the copy of each your atoms would behave slightly differently. At least if I understood the uncertainty principle correctly, see also this on Physics SE.
But your thought experiment features god, so don't let Physics stop you.

  • Yes ;-) it would not matter (in sence that we wont really notice) if the world was deterministic in this sense. Just that you dont have a free will. My question wasnt if the universe is deterministic, because im pretty certain about that, it was if there were any philosophers how maid a case agains determinism. To widen my horizon on this subject.
    – yamm
    Commented Feb 25, 2015 at 13:47
  • then the answers going into more depth on QM and uncertainty are more interesting to you. You seem to take my rephrasing with humor, that's good, wasnt sure if I came across as mean.
    – mart
    Commented Feb 25, 2015 at 14:02
  • And just to be clear, I think you misunderstand the uncertainty principle as some sort of current limit of our understand or some sort of observer effect, judging from the last paragraphs of your question.
    – mart
    Commented Feb 25, 2015 at 14:07
  • I dont not understand Heisenberg's uncertainty principle, but its not a long time since we though its not possible to land a man on the moon. So it could be that we understand QM sometime in the future. I dont want to dismiss all the knowledge we have to day just because it will get 'overthrown' in the future but i wont accept it as a single argument to defeat determinism. You convinced me to try to learn a bit more about QM. But im not convinced it will convince me^.
    – yamm
    Commented Feb 25, 2015 at 15:43
  • Although we may not have any say in whether or not we come to discover/believe that the universe is deterministic, the consequences of such a discovery belief are enormous, in that for many it will remove any notion of moral responsibility; a notion which currently plays a huge part in the way we view and treat each other. Commented Jul 5, 2022 at 10:33

Your assertion of predictability [which incidentally was also made by the mathematician/physicist Simon-Pierre Laplace] is now known to be incorrect. Other responders have pointed out that QM makes it impossible to know the current state of the universe exactly (since some measurements cannot be made simultaneously with infinite accuracy). Compounded on top of this is the phenomenon of chaos. Many physical systems have an underlying mathematical behavior for which the time evolution is highly sensitive to variations in the initial conditions, so that discrepancies between the measured state and the actual state grow so fast over time as to render prediction worthless (a good example of this is the mathematics of the weather, which is why they can't issue reliable forecasts past a few days in advance).

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    – J D
    Commented Mar 13, 2020 at 3:02

It seems that Heisenberg's Uncertainty Principle contradicts your hypothesis. No one can know the position and speed of a particle at the same time. Trying to find one disturbs the other. That's why science is always probabilistic, not deterministic.

  • mhh, i just did a brief amount of research and for me it just seem like something humans cant understand jet. we think now that it is random but we probably just dont understand it.
    – yamm
    Commented Jan 29, 2015 at 16:56
  • It is possible. But there is another flaw: this super-being should be out of this Universe. Where would it be? In another Universe? Would both Universes be completely separated? If so, how would this being study our Universe? If not, its Universe wouldn't influence our own? It grows to infinity, Universe after Universe, and no machine would be able to understand itself and everything else... I think.
    – Rodrigo
    Commented Jan 29, 2015 at 17:15
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    The Heisenberg Uncertainty principle can't possibly be incompatible with determinism because the Heisenberg Uncertainty principle is true under any intepretation of quantum mechanics, some of which are deterministic.
    – WillO
    Commented Jan 29, 2015 at 18:33
  • @YannikAmmann: No, it's not something that we don't understand yet. We understand it completely. We understand that the position and momentum of a particle cannot be known at the same time (and it has nothing to do with disturbing one when we measure the other).
    – gnasher729
    Commented Jan 29, 2015 at 19:04
  • 1
    In addition to Heisenberg's Uncertainty Principle making the behaviour of atomic particles nondeterministic, chaos theory makes sure that the nondeterministic behaviour a the smallest particles will influence things on a big scale.
    – gnasher729
    Commented Jan 29, 2015 at 19:05

The concept that has been formulated by physicists to address your question is called Counterfactual Determinism. Essentially, if you could go back in time and do anything (or an experiment) all over again, i.e. everything was exactly the same, would you get the same results?

Amazingly, we believe we actually have an experiment and theory that can judge this in some way. The theory is called Bell's Theorem, after John Bell. On my last reading oclf this topic, the experimental results indicated that counterfactual determinism fails, that is, if you go back in time and do it all over again you will, barring coincidence, get different results.

This, to me, points to the inherent randomness of the universe, already witnessed in quantum mechanics' uncertainty principal.

One caveat on the results, I believe you can get around counterfactual determinism's failure by accepting non-locality, that somehow an electron is in more than one place at a time.

In summary, Bell's Theorem and the corresponding evidence indicate that the universe is either nonlocal in nature or counterfactually non-deterministic. Quite strange!

  • Would you have references to support the various claims in your answer? This would give readers a way to get more information and strengthen your answer. What does "oclf this topic" mean? Commented Jun 28, 2018 at 3:21

My argument against determinism - it is boring.

  1. determinism is boring.
  2. the universe ain't boring.
  3. therefore, the universe ain't deterministic.

Given such unfathomable phenomena as existence, consciousness and time, crazy stuff such as the cosmological universe, non-locality, black holes, women, and all the stuff we cannot even begin to imagine, etc... determinism seems as exciting as a game of pool.

I mean, any child can understand determinism; given that the universe can be as crazy as it wishes, and so crazy that we cannot hope to comprehend, then why assume it is dully restricted to determinism?

Not to mention that we have evidence that it isn't.

  • Determinism doesn't limit anything. If i say a super being could calculate the future of everything thats just a concept. Humans will never reach that point (i guess). For us there is a ton to explore and there is still a lot we have no clues about. Determinism only says that the things we do we don't do them because we make a decision by our self but because the circumstances lead us to make this decision. At the end of the day this knowledge shouldn't affect you at all.
    – yamm
    Commented Feb 25, 2015 at 8:16
  • @YannikAmmann, I am afraid you did not understand my answer; also, your response is wrong since determinism is not just about things humans do, or about exploration, etc... you rather fancy a universe that may (in principle) be computed by a computer, and I believe this kind of view is just as cute as the belief of a baby that the world disappears when he shuts his eyes.
    – nir
    Commented Feb 26, 2015 at 8:06
  • @nir - is the Mandelbrot set boring? google.co.uk/search?q=mandelbrot+set&tbm=isch Commented Mar 24, 2015 at 22:26
  • @DanielEarwicker, while I would not call these pictures of Mandelbrot sets boring, I would rather stare at pictures of the universe - tinyurl.com/oclvuwx; anyway I was wildly exaggerating to make a point; I think Einstein thought the universe was deterministic, so who am I to mock him; but I still believe it is not deterministic; it is not even not deterministic; it stretches beyond our concepts, and capacity to understand.
    – nir
    Commented Mar 24, 2015 at 22:44
  • 1
    Determinism aint more boring than indeterminism, because we dont know what is going to happen anyway (we dont have the infinite computing power the OP speaks about). A good movie's ending is written on paper from even before we start watching it. Yet, a good movie is not boring.
    – armand
    Commented Mar 11, 2020 at 22:45

Determinism relies on cause-and-effect. Cause-and-effect appears to be all around us, and yet it cannot be proven to exist. Hume's essay is important: http://www.iep.utm.edu/hume-cau/


Either something happens as a result of something else that happened earlier or something happens for no reason at all. I don't think that there is any inbetween situation. So if anything in the universe happens for no reason at all (except for its begining) then the universe would be eventually truely random, which is something I don't observe. I cannot think of any way that one could prove that something that happens does not have an underlying cause. You may call this determinism if you like but it doesn't mean that we can determine these things, just that there is an underlying cause. A great argument against determinism however is that it would follow that you cannot help what you think and what you perceive as being real or logical. So you simply cannot help in thinking we live in a deterministic universe. This then makes any kind of discussion totally irrelevant. Thus there is no need for people who are convinced in determinism to engage is any kind of serious argument about its existence - they should simply relax and watch the world go by - there is nothing they can do to change anything. This really does go against what nearly everyone experiences. Maybe there is some problem with our language and perhaps even the problem statement itself. The word 'cause' is a big problem for a start. The word 'cause' requires a clear description of what we mean by 'time' and what we mean by 'something happens'. It's all too complicated and way beyond my comprehension. Good luck!

  • This looks like it could at a minimum use paragraphs. And it could use some references to the extensive literature that exists on the question
    – virmaior
    Commented Nov 26, 2016 at 6:14

There is no room for non-determinism in this world. And, I would argue nor even in a hypothetical world.

I admit, I don't know the mathematics of QM. But, when people ask us to accept that the nature is random at its fundamental level, that randomness is the universe's fundamental property, probably, haven't thought about randomness itself a lot.

Randomness - it's when you have a set of options and each time you make a choice 'absolutely' unpredictably. How does its mechanism even work, can you explain? Can you even hypothetically implement that mechanism? Is an 'absolute' unpredictability even possible?

Whatever your description of its mechanism will be (even if it's possible), be sure, it will be a complex one. Randomness isn't simple or rudimentary. So, people who urge us accept randomness as a universe's fundamental property, subject themselves to the same problem as religious people do, when they bring God into explanation. Thus, explaining complex things with even more complex one.

We have discovered 16 'elementary' particles (+higgs) and we think we are on the ground level. No, guys, we are still on top of an iceberg. More research is needed.

  • "I admit, I don't know the mathematics of QM. But, when people ask us to accept that the nature is random at its fundamental level, that randomness is the universe's fundamental property, probably, haven't thought about randomness itself a lot." I believe they typically call it probabilistic, since randomness more implies equal chances at everything; which isn't quite how it works. It seems strange to me that you're willing to throw away a theory you don't understand, dismissing it by suggesting that they haven't thought about probability much, even though it is central to the theories.
    – JMac
    Commented Mar 11, 2020 at 19:05
  • Well, I don't fight against Standard Model in general. I am ready to argue with people who bring QM as a counter argument to determinism of the universe. I might buy what Cort Ammon stated above, that QM neither disproves nor proves determinism. But, that statement under his **Indeterminism ** paragraph: "One perfectly valid way to interpret the results of decades of QM experiments is to argue that there are, at a fundamental level, some events which are completely indeterminate." There are respected scientists who adhere to that perception of the universe. Commented Mar 12, 2020 at 9:56
  • Even Feynman said something like "there are no inner gears that drive the result, nature itself doesn't know the result until the point of observation, which means universe is probabilistic". Even if we substitute 'random' with 'probabilistic' - which is, nature doesn't know in advance and then chooses how to behave, the mechanism of 'choosing' is still to be explained. Accepting it as a fundamental property sounds more like a religion to me. Commented Mar 12, 2020 at 9:57
  • Yes, we don't really know the mechanism. That's why I find it so strange that you're willing to accuse people of "not having thought of it a lot". I can get behind not just accepting that the universe is indeterminate; but this answer seems to assert the opposite without any support, whereas at least the theories of indeterminism are based on actual evidence.
    – JMac
    Commented Mar 12, 2020 at 12:00
  • You want to say that theories of determinism aren't based on actual evidence? How come that you need just nine atoms (if I'm not wrong) and everything becomes perfectly deterministic. How come that probabilistic and indeterministic universe from some certain level up loses its virginity and becomes deterministic and predictable? Commented Mar 13, 2020 at 15:10

I'll give a short answer, C.S Lewis makes what I believe is a reasonable argument against radical determinism. To say radical determinism is true would be self refuting. The reason for this is that in a wholly purely deterministic sequence the statement of anything as true or untrue is contradictory if taken in any real sense. If our actions, including or thoughts and inferences are purely deterministic they cannot measure for truth. Any conclusion that one makes would simply be a sort the dynamo effect, even what we think about the laws of logic. Reason itself would be a futile exercise

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    – J D
    Commented Dec 19, 2020 at 11:02
  • Logic arising deterministically is not necessarily incorrect or unreliable. The human use of logic has proven immensely reliable and of enormous benefit to our survival, likely because it allows us to reliably draw correct conclusions; to arrive at 'truths' sufficient to navigate an extremely dangerous world with considerable success. Commented Jul 5, 2022 at 10:38

It has been written that in the far distant future humans will be conditioned not to think all (all) things are determined and these same humans have also been conditioned to have amazing lifes. Life is truly enjoyed. Then a few wake up...


My three cents.

There is a specific sense in which determinism implies a form of predictability up to some finite time ahead.

In summary, one way to argue for this is that, in a deterministic universe the next state to happen, given the current state, is fixed and unique by definition. But our expectation of the future state necessarily also must be fixed and unique, by the same token, being part of the same deterministic universe and fixed state, at least for some finite time ahead. Thus determinism necessarily implies a form of predictability and lack of uncertainty.

This, from a different perspective, is also argued in: On Separating Predictability and Determinism, Robert Bishop

There has been a long-standing debate about the relationship of predictability and determinism. Some have maintained that determinism implies predictability while others have maintained that predictability implies determinism. Many have maintained that there are no implication relations between determinism and predictability. This summary is, of course, somewhat oversimplified and quick at least in the sense that there are various notions of determinism and predictability at work in the philosophical literature. In this essay I will focus on what I take to be the Laplacean vision for determinism and predictability. While many forms of predictability are inconsistent with this vision, I argue that a suitably restricted notion of predictability, consistent with the practice of physicists, is implied by the Laplacean notion of determinism.

So determinism implies a form of (complete) predictability and lack of uncertainty up to some finite time ahead, which demonstrably we lack. So we must live in an indeterministic/only partially deterministic universe. This is further corroborated by the irreducibly probabilistic and indeterministic nature of quantum mechanics (without hidden variables and/or many worlds interpretations being able to actually eliminate the probabilistic character of the theory and making it strictly deterministic).


Aristotle, in passing, mentions that chance was thought by some philosophers as a cause. But he neglects to give a full account of this.

I expect this influenced to description of the clinamen (or swerve) in the description of the movement of atoms. This was an irreducible random motion in atoms. This predates the actual discovery of the random element in Quantum Mechanics by roughly 2500 years.


The question of whether our universe is deterministic can IMHO be rephrased as “how much does the current state of this universe constrain the state in T units of time”?

If the constraint is absolute, if there is only one solution to the forward evolution of any state for T units of time, then the universe is deterministic in forward time. And conversely, if this universe is not deterministic, then the constraint in forward time can't be absolute for all states, and it's reasonable to guess not even for any single state. I will assume that.

Now, consider backward time. Usually we think of that as deterministic, that the past is fixed. Could there be more than one state evolution that had led to the current state, i.e., can state evolutions converge? Given the smoothness of ordinary classical measured state differences that seems almost unthinkable, but given the discrete nature of some quantum effects it's not so unthinkable any more (even though highly unlikely).

So while nobody's yet thought of any way to test this, our usual notion is that our universe is deterministic in backward time and in-deterministic in forward time. If that's correct then a copy of this universe would evolve just as this one, just that every infinitesimally short time interval yields an infinite number of slightly varying possible state evolutions.

Things get more complicated by the fact that current theory deals with two entirely different abstraction levels for physicality. In a thought experiment now known as the EPR paradox, in 1935, Einstein, Podolsky and Rosen showed that two “entangled” fundamental particles were more correlated than the speed of light limit would allow. So assuming that the speed of light really is a limit at the abstraction level of particles and waves and such stuff, the inner lower level workings of our physicality can't be totally bound by that law. That stands to reason, e.g. the laws that a computer program operates under are not the laws for the hardware platform that it runs on; they're two totally different kinds of beasts, just slightly connected. And as far as I know nothing more is known about that, just a baffling inferred law-breaking in one particular context, almost like watching a professional illusionist and inferring that what's really going on can't be what appears to be going on.

Another area where there is a very large unknown, is that of dark matter and dark energy. That all started with some observations in the 1960's I think it was, if I remember correctly, that galaxies in general were rotating too fast to be compatible with reasonable assumptions about them (e.g. holding on to their outer stars). The upshot of that is that currently there is a scientific consensus that, according to Wikipedia, "dark energy plus dark matter constitute 95.1% of the total mass–energy content of the universe", which we know essentially nothing about.

So in addition to quantum mechanics being so complex and weird that it's tantamount to being unknowable, there is the hidden internal implementation of reality, that we know next to nothing about (except the EPR), and there is the hidden matter and energy, presumed to be absolutely most, more than nine tenths, of this universe, that we know next to nothing about. In short, two very large terra incognitas, and one big extremely-difficult-terrain. And I think that means that currently it's impossible to answer simply "yes" or "no" to the question of whether all this unknown, is deterministic.

  • @downvoter: please do argue your point so that the answer can be improved or so that others can ignore you. blindly voting down, not with the courage of your convictions, is pretty ironic in philosophy site. it it very far from the ideals of philosophy. Commented May 11, 2015 at 21:35
  • @Readers: A series of downvotes were automatically corrrected by the SO machinery, but it only catches revenge/hate voting when it's bunched up in time. It's sad that some readers of Philosophy are unable to argue. But at the same time, I am happy that my arguments are sufficiently good that they do not see any way to disagree in the normal way. Commented May 13, 2015 at 10:09

The argument is reality itself. For there to be existence there needs to be, at the basic most level, components that lack reason. It's not that we don't know, it's not that we can't know, it's that there is nothing to know. If we're talking about layers "above" that, then yes reality is likely 100% deterministic, however if we're including these basic most components, reality is, by definition, not deterministic.

  • say more, please
    – alfonso
    Commented May 13, 2015 at 16:30
  • Can't tell if you're being sarcasitc @alfonso
    – YogiDMT
    Commented May 13, 2015 at 17:50
  • I think you have some interesting thoughts, but they are not developed or explained. What do you mean by, there is nothing to know at a certain level?
    – alfonso
    Commented May 13, 2015 at 18:59
  • The basic-most components of any reality have to be "self-determining", such a conclusion is inescapable. What i mean by self determining is that their behavior, even their existence, isn't based off of anything, it just is. The beauty of such thinking is that it doesn't even matter how complete an understanding of reality we have. Whether it's atoms, particles, strings, etc., it doesn't matter how deep we delve into the nature of reality, it has no affect on the conclusion.
    – YogiDMT
    Commented May 14, 2015 at 4:16
  • However, everything built upon such self-determining "building blocks" if you will, may very well be 100% "deterministic", relative to those initial components of course. Thus, giving the illusion of determinism because such primordial aspects of nature are so fundamental, so basic, they need not be scrutinized, they are accepted as is, allowing for everything built upon them to for all intents and purposes, be complete "rational".
    – YogiDMT
    Commented May 14, 2015 at 4:16

I am aware of at least two arguments:

1 . Argument of 'indeterministic intelligence':

It is arguable that our intelligence is 'physically indeterministic', and no one can make a true artificial intelligence. In another words, our intelligence does something that physical logic cannot do.

2 . Argument of 'indeterministic motion from intelligence':

If our intelligence is physically indeterministic, then we must be able of creating a physical 'motion or change' from nothing physical.

We eat food, but by our logic there cannot be any PHYSICAL relation between the food we eat and our motions, because when we move from intelligence, our motions are 'physically indeterministic' (since our intelligence is physically indeterministic).

Note I: while I am skeptical of the truth of 'theory of mass-energy conversion', even if it be true, I think does not change anything about this; that generally a pre-existing physical thing cannot be responsible for an indeterministic motion, regardless of it being motion or matter.

Note II: I think the argument of 'indeterministic motion from intelligence' violates 'conservation of energy'.

Note III: The argument 2 depends on the truth of the argument 1.


As far as I understand there are no arguments for or against determinism, because determinism is not a belief or a theory with a truth value.

In determinism there is no concept of alternative possibility. Everything happens with absolute accuracy and 100% certainty. In a deterministic universe there would be no concept of truth value.

Therefore it would be illogical to believe or claim that we live in a deterministic universe, as that would imply the existence of two possible truth values.

Determinism is by definition a state of affairs very different from reality.

  • Of course there are concepts of alternative possibilities in determinism. Just as there are concepts of unicorns. These concepts just do not correspond with reality in determinism. Thus, your argument seems pretty baseless and invalid.
    – Philip Klöcking
    Commented Jul 5, 2022 at 8:58
  • A nice demonstration of the concept of non sequitur.
    – armand
    Commented Jul 5, 2022 at 9:34
  • 1
    @Philip Please, do not conflate determinism with reality. Your "of course" argument seems pretty baseless and invalid. The concept of uncertainty is excluded from determinism by definition. Actually all abstract concepts are excluded. There isn't much thinking going on in a clockwork mechanism. Commented Jul 5, 2022 at 9:59
  • @PerttiRuismäki What is the definition you are using...? Just taking the Cambridge definition: "the theory that everything that happens must happen as it does and could not have happened any other way" in no way excludes conceptualizing things which do not exist. Same with the MW definition "a theory or doctrine that acts of the will (see WILL entry 2 sense 4a), occurrences in nature, or social or psychological phenomena are causally determined by preceding events or natural laws".
    – JMac
    Commented Jun 13 at 11:29
  • @JMac Determinism is the idea of a system where every event is completely determined by the previous event. Idea means that it is only an idea, not a statement about reality. Completely means that there is no randomness, no uncertainties or inaccuracies, no alternative possibilities. *Event" means that there is only event causation and no mental causation (=no free will). Commented Jun 13 at 12:30

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