Sunday, September 11, 2016

What's up, Presup?

This week’s discussion co-sponsored by the Philosophy department and the campus Ratio Christi student group will feature a theist arguing for the rationality of believing in the resurrection of Christ. He will be engaged in evidentialist apologetics -- the putative evidence in favor of the resurrection delivers the positive epistemic status of the belief.

Presuppositionalism is an alternative approach to apologetics. It engages in a more indirect form of argument involving an attempt to demonstrate that, unless we presuppose the God of traditional Christianity, we cannot legitimately claim to know any of the things we ordinarily take ourselves to know. The presuppositions associated with any non-Christian worldview will lead to incoherence. Are the presuppositionalists right?

Here’s an instance of modus ponens (argument I):
  1. If Patrick harmed Daniel for fun, then Patrick is blameworthy.
  2. Patrick harmed Daniel for fun.
  3. Therefore, Patrick is blameworthy.
It's valid, but what if you hold a view that’s incompatible with premise 1?

Presuppositionalists say atheists who want to make argument I wind up contradicting a presupposition of atheism: if naturalistic materialism is true, then no one is ever blameworthy for anything. So atheists affirm something (Patrick’s blameworthiness) while being committed to denying it, which is a kind of contradiction.

The claim, then, is that “You, atheist, can’t make sense of blameworthiness [also: objective morality, knowledge of the external world, logical laws] because it doesn’t make sense without a grounding supposition that God exists.” But why should we agree that if naturalistic materialism is true, then these judgments go out the window?1

Usually, instead of answering this question, presuppositionalists demand that atheists justify their belief in morality, knowledge of an external world and so on. I’m unsure what to think about this demand. Judgments about who has the burden of proof in a dispute are tricky, but it seems like a fair enough request and fairly easily met. I’ll discuss two responses. One deals with Patrick’s blameworthiness; the other deals with our knowledge of an external world.

A. Utilitarianism. Here is a perfectly valid argument (II):
  1. If utilitarianism is true, then Patrick is blameworthy for harming Daniel for fun.
  2. Utilitarianism is true.
  3. Therefore, Patrick is blameworthy.
How do you know the first premise?”

From this (perfectly valid) subsidiary argument (III):
  1. If utilitarianism is true, then anyone who violates the principle of utility is blameworthy. 
  2. Patrick harming Daniel for fun violates the principle of utility. 
  3. Therefore, if utilitarianism is true, then Patrick is blameworthy for harming Daniel for fun.
How do you know the second premises in arguments II and III?

What if the answer is that these are brute or basic truths? I’m not saying that utilitarians offer no arguments for utilitarianism (they do). But they don’t need them to defend themselves from presuppositionalists. Because, watch:

Utilitarianism is a poor candidate for a brute or basic truth for the following reasons….”

This complaint switches goal posts. It’s not relevant whether presuppositionalists think that someone else’s foundational commitments are false, wacky or whatever. Whatever reasons presuppositionalists provide here, none of them will show that utilitarians have contradicted themselves or their worldview. Because, however crappy they think utilitarianism may be as a foundation for moral judgments, what is the contradiction supposed to be?

Utilitarianism contradicts the way the world is -- the way God created it.

Wrong goal post again. This is just a wordier way of saying that utilitarianism is false. Maybe utilitarianism really is false, but why should anyone think it implies a contradiction? Remember: presuppositionalists need atheistic arguments to imply a contradiction. If the objection is simply that utilitarian arguments rely on propositions that Christians reject, then presuppositionalism doesn’t do what its advocates claim.

B. G.E. Moore famously made the following argument for our knowledge of the external world:
  1. Here is one hand [waves].
  2. Here is another [waves].
  3. There are at least two external objects in the world.
  4. Therefore, an external world exists.

Well, presuppositionalists demand from atheists a justification for their belief that there are objects in an external world. Here it is: [wave, wave].

But how do you know the first two premises?

David Lewis said Moore’s argument suggests things called Moorean facts. These are propositions that we have more reason to believe than any reason there could be to the contrary, or one that we have more reason to believe than any more foundational propositions that would purport to validate it. Here are two pretty good candidates for Moorean facts:
  • We have more reason to believe in the existence of hands than there is to believe any skeptical hypothesis concerning the external world -- that we might be dreaming, that we might be deceived by an evil demon, that we might be in the Matrix, etc. 
  • We have more reason to believe that harming others for fun is wrong than there is to believe any theory about what properly grounds moral judgments.
Presuppositionalists will likely reject Moorean facts because they tend to think of knowledge as the highest epistemic status a belief can have and where this implies certainty about the proposition. Not certainty in the psychological sense of incorrigibility; rather, certainty in the objective sense that Descartes was aiming to secure in his Meditations: indubitability. That is, in order for something to count as an instance of knowledge, it has to be possible to eliminate any grounds for coherently doubting it. Obviously, Moorean facts can be coherently doubted.

But presuppositionalists think Christianity is different because they think attempts to justify propositions without Christian presuppositions will end in contradiction. That just seems false. Presuppositionalists are objecting to the ways atheists attempt to justify their beliefs.

That’s a fine thing to do. It doesn’t deliver objective certainty about Christianity, but maybe attempting to uncover objectively certain propositions is a fool’s errand. Descartes notwithstanding, there are probably better ways to spend one’s time. As my colleague danced last week, we know lots of things by way of methods that don’t guarantee their truth.

Kyle Swan
Sacramento State
Department of Philosophy

Some arguments in this neighborhood are just bad, like Ivan’s in Dostoevsky’s The Brothers Karamazov that if God doesn’t exist then anything is permissible. Some are plausible if understood in a weaker way, like the idea that a certain understanding of morality fits more comfortably within a theistic worldview than a naturalistic materialist one and so the existence of God is the best explanation for the existence of objective moral facts.


  1. Kyle, I'm all on board with this but I wonder if we might be ignoring something about the nature of argument that makes the presup's case a tad stronger.

    In general, you seem to be saying that presup isn't really showing that the naturalistic materialist/ atheist is incoherent. Rather, she just subscribes to a view that the presup rejects as false.

    But the presup is really trying to show the naturalist that her views are false. And what this basically entails is showing her that if she thinks through the conjunction of her own views and what the presup can convince her of that there is in fact a contradiction, one that can be best eliminated by rejecting one of the naturalists assumptions.

    This doesn't affect your point insofar as it is certainly open to the naturalist to reject some key claim made by presup instead. If she does, then there may be no inconsistency and we are simply left with disagreement.

    But it seems to me that what it does show is that presup's basic move to argue with the atheist is part of a strategy to reveal the contradiction. So maybe he isn't fiddling with the goals posts as much as you suggest.

    Another more niggling point regards the criterion of certainty. Descartes' worries can be reconstructed entirely within a probabilistic framework. In other words, his worry that we can't be certain of anything can be expressed as the worry that we have any basis for assigning any nonzero probability to our beliefs whatsoever. Moore's proof that he has hands, e.g., neither guarantees that we have hands nor makes it probable. This is because we have no basis for regarding a skeptical scenario such as an evil demon or a Boltzmann brain as improbable. So epistemic certainty may not be the main issue. (Personally I think it has more to do with the fact that presup is perpetuating an incoherent Cartesian requirement, namely that to know that P we must know that we know that P.)

    1. That's fair and perhaps fairer than I was to them. The strategy you suggest is a common argumentative strategy and we all use it. Their problem seems to be that they just think it's way easier to pull off than it is in debates about morality and epistemology (and logic).

      I even agree that, at a certain point, responses to the strategy of the form "Ah, but there's no contradiction because I need only invoke implausible-claim-P, which makes the set of propositions consistent" would reveal that the strategy actually has been successful. But, again, I think presups claim they've achieved that point way sooner than they have a right to.

      That's a good point about certainty. I was thinking of the idea of eliminating all grounds for doubt and knowing that you know as basically the same, and they're not. But the idea that we know lots of things by way of methods that don't guarantee their truth is the same idea as the idea that we don't have to know that we know P in order to know P, right? And Moorean facts appeal to that idea, right?

    2. The claim that we can know without knowing that we know is mainly about rejecting Cartesian internalism rather than infallibilism, where internalism is the view that to know P we must have cognitive access to an adequate justification for believing that P. There are plenty of contemporary internalists who are (or would at least like to be) fallibilists. Conversely, an externalist would say that you could be infallibly correct about something even if you had no reflective capacities at all, as long as you were hooked up to the signal by a perfectly reliable process. I don't know of any externalists who insist on that as a criterion of knowledge, but it would certainly be sufficient.

      So the distinctions can be made. But I believe you are still right that there is a strong non accidental connection between the two.

  2. Kyle, I agree with your assessment of the arguments above. And I’m not too familiar with this literature, but based on some conversations I’ve had I think there are two strategies that might get called presuppositional apologetics. The first is what you describe. Let’s call that offensive presuppositional apologetics (‘offensive’ in the sense of offense vs. defense). It tries to support the claim: “The Christian worldview is the only rational worldview.” But there is a weaker strategy. Call it defensive presuppositional apologetics. It tries to support the claim: “The Christian worldview is a rational worldview.”

    With this latter view in mind, I take the strategy to be something like this:

    Apologist says:
    “Given starting points X, the Christian worldview is rational.”
    “Given starting points X, atheism is irrational.”

    Atheist replies:
    “Given starting points Y, the Christian worldview is irrational.”
    “Given starting points Y, atheism is rational.”
    “Furthermore, given starting points Y, believing X is irrational.”

    Apologist replies:
    “Well, given starting points X, believing Y is irrational.”

    At this point, they both appear to have the same methodology: begin with some starting points and derive a coherent worldview. The relevant question to ask is “who has the better starting points?” And evaluating starting points is notoriously difficult. How can you evaluate something without any presuppositions? So, the apologist says, “We have different starting points, but no way to evaluate one set of starting points over another. So there is no rational criticism of the Christian worldview.”

    Now, whether this strategy is successful or not is open for debate. Plausibly, some presuppositions are better starting points than others. But, at least, the defensive strategy seems more promising than the offensive strategy.

    1. Thanks, Tim. I agree with all of this, especially the suggestion that everyone has presuppositions.