I would like to know what the most successful arguments have been against necessitarianism, as I struggle to imagine how necessitarianism could be false.

I think about how any particular event transpired - say - my decision to walk left out of my building instead of right, and all I see is that the totality of the circumstances compelled me to go left. So how could those same circumstances have caused me to go right? If I were to apply this same rationale to everything that has ever happened, I am left with necessitarianism. In essence, I believe that the totality of the circumstances induce the one thing that happened, as they were apparently not the right circumstances to induce something else.

I saw the post Arguments for and against necessetarianism but I am not satisfied with the response. The author seems to base his arguments on the first sentence: "There are theoretically infinite ways the world could be", but this simply assumes the falsity of necessitarianism. The author also alludes to the "problem of origin", which seemingly suggests that an origin is necessary in the first place, but I don't understand why that need be. Perhaps I have misunderstood, in which case, I invite someone to correct me.


I've seen several comments and answers that mention how my description of choosing to go left neglects the actual thought process of choosing. It does not. I just view my thoughts, feelings, etc as pieces which comprise the totality of the circumstances. I don't view my mental processes as being metaphysically different than the wind, nor is it clear to me why I should.

  • When you get out of your building, you never hesitate between going left or right? You've never experienced hesitation in your life? In this experience, it feels like any decision is possible. So much so that sometimes people chose aphazardly, eg by tossing a coin, just to make some decision.
    – Olivier5
    Oct 6, 2023 at 17:18
  • If your motivation is "all I see is that the totality of the circumstances compelled me to go left" then this is a special case of necessitarianism called causal determinism. SEP surveys some arguments against determinism, one being quantum experiments where even electrons are not "compelled" to go right or left. But even before that, you do not actually "see" compulsion any more than others "see" freedom of choice, so if that is all there is to it necessitarianism is a non-sequitur that can be dismissed without argument.
    – Conifold
    Oct 6, 2023 at 17:52
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    OP reasons like Leibniz's pre-established harmony as one can't simply change a predicate of a substance from its complete concept without affecting all its other predicates and thus changing the whole universe, ergo pre-established determinism established. One ancient argument against it without invoking ill-defined free will was the 'sloth paradox': as everything is necessarily determined one can be sloth forever. Now if one is determined to be sloth, ceteris paribus, one already reasons 'one would act in some future' at any moment, but 'one would act in some future' just means non-sloth!... Oct 6, 2023 at 23:24
  • @DoubleKnot I believe the sloth paradox fails if you consider that an actor will only do the thing that they want to do most, given the set of possible actions. It's just that what the actor wants is determined, and the actor's ability to choose which action best suits his/her desires is determined. No slothyness required. Oct 7, 2023 at 0:58
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    Your dissolution inevitably brings in free will ("only do the thing that they want to do most, given the set of possible actions") which I've admonished to avoid at the first place ideally. This paradox is only based on purely logical argument around the key delay proposition which says 'I will act in some future'. If one proves this to oneself instant after instant of time (assuming time is discrete for simplicity) under ideal constantly static condition which by the way it makes perfect sense, then one effectively becomes sloth forever. So non-sloth means sloth! Thus against determinism... Oct 7, 2023 at 6:14

5 Answers 5


Asserting that our world is "necessary" is a VERY strong claim, and has a burden of justification on it. An inability to conceive of any other circumstance, is not such a justification, that is instead a fallacy, the argument from incredulity: https://en.wikipedia.org/wiki/Argument_from_incredulity. If that is all you have to justify necessitarianism, then necessitarianism is an unsupported strong claim. Which does not mean it is false, but also means nobody needs to refute it to dismiss it.

Meanwhile, there are excellent reasons to dismiss necessitarianism. The most notable is that -- basically there are an infinite number of circumstances that logically could be the case in our universe. The universe has reasonably been shown to be contingent by, among others, Kant in his Critique of Pure Reason.

Additionally, you seem to lean toward determinism, an even stronger form of necessitarianism. But we also know our universe is not determined. This is shown by quantum mechanics, and the Heisenberg uncertainty principle, among other justifications. See this answer about physics in general being non-deterministic:Can the universe be fully deterministic on a macro scale but not on a micro scale?

  • Thanks. Kant's argument sounds like it would be an answer to my question. Could you summarize it or provide a link to a summary? Oct 6, 2023 at 20:09
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    @DavidSilverberg sparknotes.com/philosophy/kant/section1/….
    – Dcleve
    Oct 6, 2023 at 20:18
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    @ScottRowe I do pretty much agree with you on this (that it's pointless), though I have always found the idea rather comforting as it wards off the painful feeling that maybe things could've been different. Oct 7, 2023 at 14:49
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    The "burden of justification" rhetoric dosen't take you very far as the same logic could be applied to the negation of necessitarianism; the assertion that purely contingent things exist (i.e. brute contingencies). As for the positive reason you put forth to reject necessitarianism, you seem to have presupposed the existence of brute contingencies, as the claim that logically there are other states the universe can be in is exactly what necessitarians deny.
    – Max Maxman
    Oct 11, 2023 at 18:46
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    @Dcleve What exactly is the justification for the consensus that you assert? The justification for necessitarianism lies within the principle of sufficient reason, a principle that strongly aligns with human intuition, has a strong inductive basis, and seems to be an instrumental assumption (e.g. experimental science). As for the onus of proof rhetoric, as I said before, such rhetoric rings hollow when conducting analysis. A statement of assertion can be constructed as a negation and vice versa; standards used to dictate the onus of proof are subjective and seem to lack philosophical utility.
    – Max Maxman
    Oct 11, 2023 at 19:26

Let's start with Benacerraf's identification problem. This is the problem of "reducing" the natural/counting numbers to sets. We seem to be able to proceed in at least three ways (at first just these three):

  1. Take the natural numbers as primitives of the system, i.e. deny reduction in the first place.
  2. Define them as tupletons, starting with the empty tupleton {}, procedding to {{}}, then {{}, {{}}}, and continuing onwards like so.
  3. Define them as singletons of their predecessor, down again to 0 = {} and 1 = {{}} but 2 = {{{}}}, etc.

But we can modify both (2) and (3) by having at least 0, or also 1, or also 2, or also... however finitely many of the finite n as primitives over which the remainder of the naturals are "constructed." So as the SEP article linked to says, there seem to be infinitely many set-theoretic ways (indeed, infinitely many branching such ways) to introduce the simplest class/category of numbers of all.Q

Next, real numbers too might be taken for primitives, or as infinite sets of rational numbers (or complicated interpolants of infinite natural sequences), etc. Infinitesimals in turn have been conceived of as elements of the set of nonstandard/hyperreal numbers, as "syrupy" pseudo-points vaguely extracted from an otherwise indecomposable continuum, or as surreal reciprocals of transfinite ordinals.

Now, if the mathematical basis of the concept of functionality is so diversified, what other basis do we have, besides mere feelings of pressure under action, for thinking that we are necessitated to act by our place amidst the functionality of our world? For if those functions are themselves partly (perhaps mostly) subjective anyway, and our subjectivity is so ambiguous and even vague, what even subjective evidence do we have (besides, again, in feelings of compulsion) that everything is necessitated at any time?

QYet another option is to start the cumulative hierarchy from a Quine atom. This option is related to various ways to well-found a numerical universe from a parafounded basis, e.g. by taking the function WF(At) where WF(x) is a generic well-foundation function and At is a class (possibly proper) of Quine atoms.

Note that we have so far discussed only mathematical pluralism. When it comes to logical pluralism, we have also to ask about the multitude of definitions of necessity, among other things, which quite complicates the matter (and testifies further against amorphous feelings of our will being forced to exert itself in exact ways all the time).

  • Thanks, I may need some time to conceptualize your analogy. Also I edited my question. Oct 6, 2023 at 19:29
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    @DavidSilverberg I was hoping that the argument would come across as a direct one, not as an analogy... and I was, to a great extent, defending Pertti Ruismäki's statement about how there are infinitely many ways the world can be in general. But so if the necessity of necessitarianism is already multiple in essential nature, howso should it really force the world to be only one way, every day, everywhere? Oct 6, 2023 at 20:15
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    "Argument by flummoxing" ha ha
    – Scott Rowe
    Oct 7, 2023 at 12:35

Necessitarianism applies in some cases of causality and does not in others. Whether you will take left or right is not sometimes pre-determined. However you will age and die for sure. Here necessitarianism applies. Because you took birth , you will age and then you will die. Why you took birth ? You took birth because your parents had sex ? Why did they had sex ? Because they were craving for it in their youth ? Why they were craving for it ? Because it felt good. Why did it feel good ? Because sex makes tender contacts. Why they made contact ? Because they had sense organs. Why they had sense organs ? Because life evolved in the planet. Why did life evolve ? ( from here on you can answer yourself)

Thus we see necessitarianism applies to some cases of causality and does not apply in other cases or weakly applies in some cases.


Personally, the most powerful and elegant argument against necessitarianism that I am aware of is the idea that Popper reportedly presented to Einstein, in his effort to convince the latter that determinism ought to be abandoned. According to Popper's The Open Universe -- An Argument for Indeterminism (in fact a large collection of arguments, highly recommended), this argument gave Einstein pose.

It's about the usefulness and meaning of time. If the universe is "closed" i.e. fully determined from the onset, then there is never any real novelty in it. Each and every second that passes offers only a repetition of the previous second. It is fully redundant. Therefore, a determinist universe would be a colossal waste of time, whereas an indeterminist ("open") universe is creative and full of possibilities, and thus has some use for time. All these billions of years are meaningful within indeterminism, as opening up the possibility for novelty and change, but they are totally wasted in determinism.

Why have time, if time brings nothing new, ever?


I tried to approach necessitarianism by asking the question "What makes something necessary in the first place?" That led me to the question of origin.

If an event is deemed necessary, that means only that the Universe happens to be/was created that way. There is no necessary way the Universe must be. Only the consequences of the initial conditions are seen as necessary.

The fact that necessitarianism does not explain why this is necessary, but that is not, makes it an invalid proposition.

There is an error in your thinking also. You think that the circumstances forced you to go to the left while in reality it was your own choice. Your turning to the left was not necessitated by the circumstances. The circumstances did not send neural control signals to your muscles, your own brain did. You decided that, considering the circumstances, turning to the left is what you should do.

As turning to the left was not necessitated by the circumstances, necessitarianism seems like a useless idea that explains nothing.

  • Thanks for your response. I edited my question to clarify what I mean by "totality of the circumstances". Oct 6, 2023 at 19:28
  • @Pertti Now I believe I understand your point, but the existence of an initial condition suggests that there is in fact a "beginning", and I haven't seen a compelling reason to strongly believe that this is the case. Yes, there was a big bang, but there at least existed a singularity prior to that. Oct 7, 2023 at 14:56
  • Regardless of whether there was a beginning the contents of the Universe must be determined somehow. Necessity does not explain why the Universe looks like this and not some other way. Oct 7, 2023 at 19:59

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