If one can justify disbelief in theism, what repercussions does this have on the monotheistic faiths?

Is justifying disbelief in theism enough to warrant disbelief in Islam, Christianity and Judaism, too?

I think that the truth of theism is a necessary condition for monotheistic faiths.

  • You haven't defined theism. You assume that monotheism is a subset of theism. It may be or it may not be. You need to define your terms to determine if there is an intersection.... Mar 16, 2015 at 5:23
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    sounds reasonable to me. because these monotheistic faiths are presumably theistic. i know there are Jews and Unitarians and Quakers that seem to be part of a faith community who are, themselves, atheist. i don't quite understand all of it. Mar 19, 2015 at 22:10
  • Theism is a loose label to place on the three great monotheistic faiths; for example the formula of the Trinity (the Father, Son and Holy Ghost) makes no sense within Islam. Mar 25, 2015 at 14:39

3 Answers 3


If one is warranted in believing that theism is false, then, insofar as Islam/Christianity/Judaism/etc. endorse the truth of theism, then one will be warranted in believing that Islam/Christianity/Judaism/etc/ are false too. There's a general epistemic principle at work in the background here: if you're warranted in (dis)believing that P, and P entails W, then you're warranted in (dis)believing that W.**

That principle looks prima facie plausible, but we might want to add a further restriction to the antecedent, that you're aware that P entails W. So if you don't know that P entails W, you can justifiably believe that P while not believing that W.**

You're correct when you say that the truth of theism is a necessary condition on the truth of the system of beliefs endorsed by the religions you list. At least insofar as those religions endorse the conception of God given by theism. And you're correct to think that if you're justified in believing that theism is false, then you're justified in believing that the claims made by religions that endorse theism are false too. But only if you're aware that those religions endorse theism (which looks like a pretty plausible assumption).

** This is related to, but not identical with, the epistemic closure principle. See more here.

  • "if you're warranted in (dis)believing that P, and P entails W, then you're warranted in (dis)believing that W." Could I ask what "P" and "W" represent in this specific case? Assuming that "P" is theism and "W" is monotheisms, is it really the case that theism entails monotheisms?
    – Five σ
    Mar 15, 2015 at 19:50
  • 'P' and 'W' here are propositional variables. They stand for any proposition whatsoever - you can think of a proposition as what is expressed by a well-formed declarative sentence (very roughly, but we don't need to go into that). What you cited is the epistemic principle that warrants us in disbelieving in the religions you cite, if we're already warranted in disbelieving theism. Now, here's what the principle says. If 'P' is the claim 'theism is true' and 'W' is the claim 'monotheism is true', then, since monotheism presupposes theism, if we don't have reason to believe in theism .. Mar 15, 2015 at 20:08
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    Cont'd. we don't have reason to believe in monotheism either. This is because the truth of theism is a necessary condition on the truth of monotheism - if monotheism is true, then theism has to be true too. So if we don't have reason to believe in theism, it seems we don't have reason to believe in monotheism either, since we've lost one of the things we needed for the truth of monotheism. So you're correct that theism doesn't entail monotheism, but that isn't what the principle says. The principle is about what we have reason to believe, given what something entails. Mar 15, 2015 at 20:11
  • Aha, I appreciate the explanation.
    – Five σ
    Mar 15, 2015 at 20:11
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    Glad I could help! Mar 15, 2015 at 20:21

The three faiths referenced have some significant differences. There is a fairly sizable number of atheists who consider themselves "culturally" Jewish, and there's a certain extent to which the religion focuses more on behaviors than beliefs. There are also people who consider themselves "non-theistic" Christians --followers of Jesus as conceptualized as a purely human rather than divine teacher. The mainstream Christian church, however, definitely does not accept such people as actual Christians. "Non-theistic Islam," on the other hand, doesn't even make sense as a theoretical concept.

With that said, when each religion is considered in its core, theistic form, each presupposes the existence of God as foundational. It's hard to see any way clear to make a statement of the form "I don't think I'm justified in believing in God, but I do think I'm justified in believing that the religion of Christianity is right."

It might be the case, however, that a specific religion conceptualizes God in such a way that there is new and better evidence for that view of God than for the more general one you previously rejected. For instance, Kierkegaard's existential Christianity embraces the absurd. When considering God in the abstract, you might take certain perceived absurdities as counter-evidence. If you came to embrace Kierkegaard's perspective, however, you might no longer find that counter-evidence decisive.


Some forms of monotheism might not be unjustified even if Theism is unjustified.

Here is the example of Christianity that might not be affected even if disbelief in Theism is justified. Jesus said, "The kingdom of God is within you" (Luke 7:21). Carl Jung held a view like this, although it wasn't expressly Christian (https://thesethingsinside.wordpress.com/2013/01/07/carl-jung-says-god-is-reality-itself/). He held that God is the collective consciousness that resides in all of us together. These are two of the most important religious thinkers in the history of Western civilization.

By contrast, in classical Theism, God, if He exists, stands external to a human's consciousness. According to Cudworth, the originator of the term theism, "Strictly and properly called Theists [are those] who affirm, that a perfectly conscious understanding being, or mind, existing of itself from eternity, was the cause of all other things" (Cudworth, Ralph (1678). The True Intellectual System of the Universe, Vol. I. New York: Gould & Newman, 1837, p. 267). Note well "existing of itself from eternity," an assumption not held by Jung or Jesus of Nazareth.

So disbelief in an externally existing God does not necessarily transfer to a brand of monotheism where God exists internally. I am not saying that disbelief in Theism is not justified (or giving reasons for or against the justification of Theism or the Jung/Jesus variety of monotheism); rather, I am saying that justification in disbelief in Theism only has as its object a very specific theology that is not universally shared by monotheists, which I have proven.

Thus, even if you were to argue that Theism is unjustified, you would still have work to do to prove that all forms of monotheism are unjustified.

  • There's a lot going on in this answer, but I don't really see how this is answering the impact of justified disbelief on theism. Can you make it clearer?
    – virmaior
    Jul 7, 2015 at 4:16
  • Virmaior, the original question is not about the impact of justified belief in non-theism on theism, but on actual momotheistic faiths. Yes? A lot of times there is a mismatch between living faiths and what critics call theism. So, for example, some Christians deny evil. It's all according to God's will. And God's will is good. Thus, ultimately speaking, there is no evil. This short curcuits the main justification for nonbelief - the problem of evil - to their living faith. Better, many believers see God as inside them. But all proofs for the nonexistence of God focus on His alleged external r Jul 7, 2015 at 14:33
  • I've converted what you posted as a second answer to a comment...
    – virmaior
    Jul 7, 2015 at 14:44
  • The crux of the question is the consequences of justified disbelief in theism. This is not whether or not belief is justified -- which is what your comment and answer seem to focus on. Instead, it is what follows if disbelief in theism is justified. Justification is a term of art in epistemology.
    – virmaior
    Jul 7, 2015 at 14:45
  • Instead of "stands external" might one say exists in some way beyond an individual's consciousness?
    – virmaior
    Jul 8, 2015 at 2:09

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