Why can't free will or free choice exist in a 'totally' deterministic universe? What I mean by a 'deterministic universe' at least 'locally' is one where if you had 'enough' information regarding some 'locally' observed set of events and you had enough knowledge and computing algorithms ( in your hand held computer say) you could calculate with great accuracy various things that will happen in the next few moments within the observed events. But of course this sort of 'puts' you into the position of an outside or independent observer UNLESS some of the things you yourself do effect the needed calculations or the events themselves. Everything in this locally observable environment could be very accurately 'modeled' with computing algorithms that make great predictions what will happen next as long as your own actions as a non-independent observer don't interfere with the 'progress' of the events being observed. (Or nothing else interferes also) So the whole locally observable environment is 'deterministic' yet you can keep changing things or interfering with a set of observed events with various degrees of 'alterations' WHILE the events are taking place. So any analysis of whether the computing algorithms or predictive models are 'working' will have to 'wait' until the 'interfering changes' have occured.So assuming we can interfere with any set of events in how they unfold everything 'else' ( not counting ourselves) can be regared as deterministic events. Is this a way to reconcile determinism and free choice or free will?

  • Were the interfering changes not governed by the same deterministic laws?
    – nir
    Dec 27, 2014 at 9:43
  • Yes , but the determining of which way to interfere with a situation , if one is aware of many distinct ( mutually exclusive) ways ; is not governed by deterministic laws. ( If it was Liebniz would have been right ; and two people who have a conflict with all sorts of competing motives could sit down have a machine plug into their brains and someone could say 'Let us Calculate!' The machine could then analyse all the motives of the two people in this conflict and with deterministic algorithms show the exact reasons for each set of motives and measure who has the best position.)
    – 201044
    Dec 28, 2014 at 2:45
  • how is this about free choice in a deterministic UNIVERSE as the title of the question declares?
    – nir
    Dec 28, 2014 at 6:21
  • The interfering changes are not governed by the same deterministic laws. If someone could list 101 ways to interfere with some process he is about to interfere with then which method he chooses is not determinable by some strict governing laws that can somehow 'read' his mind 'indirectly' and say with great accuracy which method he is going to use. The fact he can choose to interfere with said process in various different ways which are not predictable ( because even if one comes up with all the relevant 'variables' he can always add new ones); this shows his choice is unpredictable.
    – 201044
    Dec 30, 2014 at 5:01
  • didn't you practically write the following circular argument? "The fact he can choose ... in ... ways which are not predictable ... shows his choice is unpredictable"; I believe circular arguments are invalid. Regardless, the kind of universe you are describing does not seem deterministic; consider for example the Wikipedia definition: "Determinism is the philosophical position that for every event, including human action, there exist conditions that could cause no other event"
    – nir
    Dec 30, 2014 at 8:50

4 Answers 4


The issue is that we define it that way

We like to think of ourselves as having "free-will," well most of us do. However, the definitions of what "free-will" mean get very difficult in a perfectly deterministic scenario. We would need to come up with a system which can define something people accept as "free-will" but which is not in conflict with determinism.

One thing that will give solace: the current Quantum Mechanics(QM) theories predict that it is impossible to fully measure a waveform without disrupting it. This means that a QM "particle" can be considered to have freewill. It can act in a completely unpredictable way, so much so that we have Quantum Encryption built around the theory that it can never be predicted. This "guarantee" can hold until QM is superseded by a new theory with different rules (which happens to all scientific theories). This approach to free-will may be nullified if the new rules prove that perfect measurement without disruption is possible.

So what about macroscopic systems? Consider a chaotic system. Chaos theory is still in its infancy, so definitions of chaotics systems are still in dispute. However, three criteria seem to be generally accepted:

  1. it must be sensitive to initial conditions;
  2. it must be topologically mixing; and
  3. it must have dense periodic orbits.

The first and second combine to an interesting result: if the act of measuring the "being" disrupts it in any way after measurement (akin to QM interference), then that disturbance is quickly mixed into the rest of the system, and the system "evolves" differently than the simulated version. It has maintained freewill.

There is a timeframe, known as the Lyapunov time. It is a measure of how long it takes before a system becomes chaotic and hard to predict, given some initial information. During that region, your measured version will match very well to the real version. This suggests that freewill has been violated, or does it? On the scale of a few miliseconds, is the position of your body hard to predict? Freewill seems to be concerned more with the long term behavior.

  • What you describe involves very technical points and would not account for the 'common sense' view ( or what might be called the 'naive- philosophical' view) of what free-will is. I think a simple way to define free-will without all these problems is to say if any type of dynamic system can change itself without being restricted by any previous system states or processes then the system has a type of free-system-variation or a technical version of free-will. That is if a system can change itself 'freely' without being restricted by itself or outside 'sources' it can 'act' freely.
    – 201044
    Dec 30, 2014 at 4:50
  • @201044: It is an interesting word to define, isn't it. I have had major issues with the "common sense" view in the past. Your previous system state DOES matter -- if you are inside, and you want to be outside, you don't get to simply teleport outside; the previous position of your CG matters. If someone connects with a left hook, you do not have the ability to ignore their effect on your internal state. If you are bad at bluffing, you cannot call a hand without revealing your internal state. Restrictions abound, and that's what makes the definitions so interesting.
    – Cort Ammon
    Dec 30, 2014 at 6:18
  • Now if you subscribe to dualism or idealism, where the consciousness is a non-physical entity, the "common sense" view works well. However, much of your question's wording regarding local information vs. global information suggested a physicalist point of view. If that was not your intent, then the extreme wording I use to bend a deterministic physical world to admit free-will may not be necessary.
    – Cort Ammon
    Dec 30, 2014 at 6:20
  • What I find interesting is that we like to believe we can do anything thanks to free-will, but we are statistically reliable. We can go on a murder spree, but statistically speaking, society rely on most individuals not murdering most of the time. We predict that most 'free-willed' individuals will choose not to murder. The fact that an individual apparently can do anything, but shows statistical preferences is intriguing. It appears many of these behaviors are learned, suggesting others DO have an long-term effect on our free-will, it is just really challenging to pin down.
    – Cort Ammon
    Dec 30, 2014 at 6:29
  • 1
    @201044: Ahh, that makes sense. I was going after a slightly different wording in order to admit freewill as part of a deterministic physical realm by defining a physical "self" which cannot be predicted perfectly by any external "other" because of chaotic effects. In fact on timescales greater than its Lyapunov time, it is completely unpredictable. Such "physical freewill" would be completely indistinguishable from any "metaphysical freewill" from within the system barring any "metaphysical measurement devices" which work outside of physics to identify "true" consciousnesses.
    – Cort Ammon
    Jan 1, 2015 at 19:46

Newcomb's problem might help us understand our difficulties between freewill and determinism. There are two boxes; one box is opaque and the other is translucent. In the translucent box is one thousand pounds. The opaque box contains either a million pounds or nothing. There is an omniscient being capable of accurately predicting our choice before we execute it. If the being predicts we shall take only the contents of the opaque box, there shall be one million pounds in it for us to share. However, if we select the contents of both boxes, there will be nothing in the opaque box. According to the principle of maximizing expected utility, we should select only the contents of the opaque box and leave the other one alone. However, according to the principle of dominance, we should select the contents of both boxes because our action occurs after the contents of both boxes are already set up by the predictor. Here is the difficulty with the principle of maximizing expected utility: Suppose we decide to take the contents of only the opaque box. As we walk away with our loot, we look back at the transparent box and realize there is a thousand pounds in it. What is stopping us from going back and taking it? After all, we already received the million pounds and the thousand pounds in the translucent box just cannot disappear into thin air and we would also prove the predictor is unreliable. Suppose, we open the contents of just the opaque box and find nothing, then we can just leave the other box alone, it's just a paltry thousand pounds, to prove the predictor is unreliable. So, an omniscient being capable of accurately predicting our actions, in a deterministic universe, can easily be shown as being unreliable by doing as outlined above. I believe we have freewill (determinism doesn't pass muster), as we are able to outwit an omniscient being.

  • If there are deterministic principles governing any of the choices one makes 'using free will' then if these governing rules are accurate you don't need any omniscient being in Newcomb's Problem. the 'governing rules' can be substituted for the omniscient being. The 'governing rules' would be capable of accurately predicting our choice before we execute it , if run like a set of algorithms.
    – 201044
    Jan 1, 2015 at 18:36
  • The omniscient being doesn't necessarily need to be all knowing, but rather with the perfect ability to predict our choices prior to us making them. Free will is necessary or our choices do not really matter. Jan 2, 2015 at 19:01
  • Is 'free-will' an ability to do 'one thing' ( instead of possibly others ) independently of ANY 'outside' influences or 'changing forces'?
    – 201044
    Jan 5, 2015 at 17:12
  • A person can be in an deterministic universe and still behave with free will or in a non-deterministic way. So assuming every set of actions of anything is deterministic in that given enough information of the things and processes one can determine how the actions are occurring and what will happen next. One might say a person's 'mental' actions are just 'activities' 'within' determinism so no 'free-will'. YET determinism only applies if one has 'enough' info. and the ONLY person who could 'collect' enough info. is the person themselves. Anyone else would not be in the 'persons shoes'.
    – 201044
    Jan 8, 2015 at 23:23
  • 1
    @201044, thank you, that helps. The predictor in Newcomb's problem is reliable and is able, by determinism, to know what choice I shall make. But remember, the predictor must go first, it must fix the contents of the boxes before I make my choice, since the contents of the boxes cannot be causally related to my eventual decision, I should select both boxes. However, if I do so, the predictor would know this an leave me nothing in the opaque box. But if I open that box first and find nothing, there is nothing to prevent me from just walking away, to prove the predictor is wrong. Jan 14, 2015 at 18:14

Freedom of choice must be defined before talking.

We may define from the perspective of negative liberty: I can do what I want with my resources (body, mind, stuff I am allowed to use ...) because I don't have external factors (this concept is usually tied to human violence) that would threaten me if I take certain action courses. It also sounds that NL can be expressed somehow as a sentence inside the PL.

We may define it from many perspectives involving positive liberty (I would call them "degrees"):

  • Positive liberty "as long as I can do whatever I know now and fullfill my needs". Althought this approach is the one supported by socialist governments, I could take it out from the politics scope to this practical scope: "I would like to do X. Can I?"
  • Positive liberty "as long as I can do whatever I can imagine". This is harder, but perhaps thinking about teleporting or flying could match here. This one has problems because I could imagine stuff that is actually contradictory in the physical world.
  • Positive liberty "as long as I can do whatever I can imagine, and I can imagine anything without dependence on previous events of my life". For non-believers in the soul, it is frequent that they argue that our generated ideas came from stuff that happened and happens (similar to the brain being a state-machine or actually more-than-just-close-to a neural network computing model).
  • Positive liberty "as long as I can include the idea of randomly generating AAAANYYYY idea at all" (like being absolutely able to describe any crap from inside the tao, either whether I currently have language tools to describe it, or not). This could also include the concept of "ideas that somehow cannot be thought by any human" (and I'm a human and I think the OP is also one).

If your definition of liberty is 1 (negative) or 2 (positive in the main needs), you will have no trouble at all with a deterministic world. Deterministic world has no place to random, but these definitions do not imply random at all.

Please note that certain recent news regarding QP described that the universe does not seem to be deterministic (God plays dice) at the quantum level (this does not talk about the macroscopic levels like human body). But let's analyze the cases 3, 4, and 5:

  • What can you imagine? Can you imagine alter the time (the past events) to disallow you ever being free-willed?
  • Can you generate a thought independently from past events? This adds a problem to neurologists and scientists of many disciplines, althought not to religion-based disciplines. The problem in the former point still exists.
  • Can you generate any thought? Do you have all the tools to generate any thought at all? I dare you to say "I want to buy exactly an amount of X lb of bread" and replace X with absolutely any irrational number (irrational numbers you can think about are enumerable since they come from known mathematical operations and finite numbers you can enumerate; however irrational numbers are not enumerable and so there's like m^K (m > 0; perhaps CH is true) numbers you cannot even imagine, where K is aleph-0). So to generate ANY thought you need an infinite brain size (irrational numbers are made of infinite fractional positions).

No: there are cases you cannot even try to figure, like case 5.

Yes/No: If we can choose to not count the quantum level, we can say our brain is deterministic and so we cannot make it in the case 4. Otherwise we can. It is not proved (don't think if ever studied, or at least don't know about) that such quoted news' described effects reach the neurological/cellular level.

Yes: there are cases you can accomplish in a deterministic world. Case 1, 2, 3, provided that in case 3 you don't enumerate a thinkable-but-contradictory thing.

  • If there is no free choice and the 'universe' is deterministic , in that one can given enough info. and enough time predict any finite sequence of behavior as to it's outcome then no one can actually believe in anything..Because any 'set' of ideas that one thinks is 'probably' true, one has no free choice or free will ( according to the assumptions). One HAS to ascribe to a set of ideas one 'has' because everything is deterministic and no one has a choice in 'changing' the set of ideas they think are true.
    – 201044
    Dec 8, 2015 at 7:42
  • Another way to see , in a deterministic world one can't believe in anything because the sets of ideas one 'has' one must follow them as one has no free choice to choose to change these set's of ideas or reconfigure them.; So if one is looking for arguments to support the claims there is no free will or free choice and there are more than one useful set of arguments for this ; what does one do then? One can't choose between the arguments. One can't settle on one specific argument as a choice....
    – 201044
    Dec 8, 2015 at 7:49
  • By definition (Fides et Ratio), faith/believe is an act of choice. If choice is not free, so neither is faith. But saying that faith is not free (of its deterministic nature) is not the same as saying it does not exist. It is also bound to the expected definition of freedom you want to use.
    – user14065
    Dec 8, 2015 at 14:53
  • If faith or belief in something is not free because one can't choose whether to maintain the faith or belief system or change it then it's like a belief without any substance. If one says one believes in something this implies they are willing to maintain it against criticism or doubt ; they are willing to 'keep the belief going' as it is an ongoing process and as knowledge systems change belief systems are 'maintained' or not. If one has to believe in something because of their present 'states of existence' due to determinism then they can't maintain this as it has to be this way.
    – 201044
    Dec 20, 2015 at 6:10
  • It may be without any substance, indeed. EVERYTHING would lack of substance for someone who becomes aware that free choice (free wrt determinism) does not exist.
    – user14065
    Dec 20, 2015 at 23:29

We must understand that free will is not dependent on determinant or indeterminate nature of the world. If there is no principle possibility to determine what will happen on next step, this does not implicate that free will exists, because results will be symmetrical to situation if there is no free will. Also, if any next step is determinable it also has no problem for free will, because free will doesn't mean random choice, any choice has it's reason, free will is "acknowledged necessity". So, determinism or randomness of the world dose not tell us if we have or not have free will.

P.S. It was big problem in early period of Christianity, because by Christianity we have freedom of choice, but god is omniscient.

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