Monday, July 15, 2024


Why Presuppositionalism Is Wrong

by Francois Tremblay

Presuppositionalism, also called the TAG in its more specific form, is the most popular form of Christian apologetics today. It is easy to see its attraction. Contrarily to classical arguments, which seek to establish evidence for the god-concept, presuppositionalism seeks to show that naturalism is inadequate and therefore presupposes the existence of God. As such, the theologian’s case becomes much more negative, and thus much easier to defend. As long as he can prove that naturalism fails to account for some fact, he can retreat to God as a default position.

We can express the argument simply in this form:

  1. There are a number of features of human understanding, such as logic, consciousness, science, morality, meaning, and so on, which the atheist uses, and which we can designate as X.
  2. The atheist position cannot account for its use of X, because…
    1. Materialism fundamentally cannot account for X, because of the properties of matter.
    2. Materialism fundamentally cannot account for X, because of the properties of biological evolution.
    1. Materialism cannot account for the existence of scientific laws, which require omniscience to be known, but are necessary for X.
  1. Only theism (with a god as Creator) can justify our use of X. The atheist implicitly presupposes theism when he uses X.


    I have already disproven the position (2b) in my article ‘Cutting Off One’s Head: The Theological Attack Against Cognition’. In it, I use a lecture by Plantinga to point out the basic flaws of this evolutionary objection: the fact that it confuses instinct with epistemology.

    Our instinctual behaviour does have a formative effect on our reasoning, but certainly the two are not directly related. To state that the uncertain status of our instincts makes all human reasoning incompetent is to commit a genetic fallacy (the fallacy whereby the origin of a proposition is judged instead of the proposition itself).

    The position (2a) is equally fallacious. In this case, we can apply the fallacy of composition. The reasoning of the theologian in this case is that matter does not contain properties such as logic, consciousness, morality, and that therefore no material system can contain those properties. But we cannot infer properties of the parts to the whole, insofar as the human mind is not a set of banging atoms but rather atoms which are assembled from birth to serve specific cognitive purposes. This is called emergentism – the fact that units, having a specific nature, assemble accordingly with that nature (a phenomenon we call “causality”) and form higher systems with new potentialities.

    If the theologian then protests and asks us “maybe emergentism is true, but why is reality arranged in this way? How can you justify emergentism?”, we shall have to ask him to complain to reality, not us. Reality is how it is, and that nature is a necessary fact. Emergentism is a fact of reality whether one likes it or not. Atoms form neurons, and neurons form nervous systems. Cells form brains, which form awareness. How this arises, is the role of science to find, not philosophy. But asking “why” it arises, makes as much sense as asking the theologian why God arose.

    Position (2c), on the other hand, cannot be corrected by a logical fallacy but rather by pointing out its false assumption. The theologian presumes that omniscience is necessary to formulate a law of reality, but this assumption is completely unscientific. The underlying premise is that knowledge presumes certainty, which is both antiscientific and irrational. We can express this underlying argument as such:

  2. Certainty is necessary to hold a law as true.
  3. To hold certainty, we need to know directly that the law will hold true in all places and at all times.
  4. The scientist is not omniscient, and cannot confirm a law directly in all places and at all times.
  1. Scientific laws cannot exist. [from (i), (ii) and (iii)]

    But (i) is false, and the whole edifice of this position crumbles. Our knowledge of naturalist laws does not rest on an impossible demand for certainty, but rather on facts.

    We can use the law of gravity as an example. For the purposes of discussion, I will use Newton’s Law as an example, although I am aware that Einstein’s formulation is more accurate. We claim that the attraction between two bodies is proportional to their mass and inversely proportional to the square of the distance between them. No one, not even the theologian, would deny this. But he would ask us to justify how we know that this applies with certainty, that is to say, how we can observe this in all places and at all times.

    The fact is that we have an extensive body of experiments and observations proving this law, and so we propose that the law will apply everywhere and at all times. But we do not believe that this will be the case regardless of the evidence – we do not hold this as certain. On the contrary, if one found that the law of gravity did not apply in some case, this would be an impetus for changes in our understanding. And we did indeed find such exceptions, which makes Relativity a better solution in some instances.

    We think that a law is true, that is to say that it applies to all places and all time, because we think we have found something about the specific nature of what we are studying – in this case, matter itself. We may, of course, be wrong about that. Only by studying this specific nature directly, and finding the proper theory about it, can we be sure that our law really applies to this specific nature. But in no case does knowledge of what should happen at all places and all times presume direct observation of such places and times. All we need is sufficient evidence to presume that we have found something about the specific identity of what we are observing.

    Because of this, we are perfectly justified in holding a law as true, and thus in holding any X as true.


    In my book “Handbook of Atheistic Apologetics”, I detail five further objections to presuppositionalism, which I will examine in turn. I will also discuss a sixth objection.

    I. The Transcendental Argument for the Non-existence of God neatly disproves (3). That is to say, given that theism entails unacceptable consequences, we must reject it as a viable alternative. Michael Martin, who constructed this argument, expresses it as such:

  2. Consider logic. Logic presupposes that its principles are necessarily true.
  3. However, according to the brand of Christianity assumed by TAG, God created everything, including logic; or at least everything, including logic, is dependent on God.
  1. But if something is created by or is dependent on God, it is not necessary—it is contingent on God. And if principles of logic are contingent on God, they are not logically necessary. Moreover, if principles of logic are contingent on God, God could change them… So, one must conclude that logic is not dependent on God, and, insofar as the Christian world view assumes that logic so dependent, it is false.
  2. Consider morality. The type of Christian morality assumed by TAG is some version of the Divine Command Theory, the view that moral obligation is dependent on the will of God.
  3. But such a view is incompatible with objective morality. On the one hand, on this view what is moral is a function of the arbitrary will of God; for instance, if God wills that cruelty for its own sake is good, then it is. On the other hand, determining the will of God is impossible since there are different alleged sources of this will…and different interpretations of what these sources say; moreover; there is no rational way to reconcile these differences.
  1. Thus, the existence of an objective morality presupposes the falsehood of the Christian world view assumed by TAG.
  2. Miracles by definition are violations of laws of nature that can only be explained by God’s intervention.
  3. Yet science assumes that insofar as an event has an explanation at all, it has a scientific explanation—one that does not presuppose God.
  1. Thus, doing, science assumes that the Christian world view is false.

    It should be noted that this type of argumentation applies to any other X. Any necessary X or any necessary part of X must be contingent in the view of divine causation, and therefore contradicts the existence of X. As such, by affirming the necessity of X, and demanding us to justify it, the theologian is shooting himself in the foot. If divine creation is true, then this universe is left without absolutes and without necessary facts. Only atheism is compatible with such absolutes and facts.

    Theologians have attempted to counter this line of argument (which I call materialist apologetics) by claiming that all X are an integral part of God’s nature. But this contradicts the transcendental argument itself: if an X is an integral part of God’s nature, then it does not depend at all on divine causation to exist. Furthermore, it presumes that some attributes of human cognition are immaterial in a fundamental way, since they can exist without matter, a position which is grounded in the discredited position of idealism. The upshot of this objection is that either the theologian must plunge in noncognitivism, in that he is talking about a conception of an X that is immaterial, or must concede that God is not necessary at all.

    II. To presume that X cannot be explained by naturalist explanations is an argument from ignorance. In fact, the rational worldview is perfectly capable of explaining any X. I detail a number of such examples in the Against section. See for instance ‘The Case for Objective Morality’, ‘In Support of Secular Foundationalism’, and ‘The Infallibility of Sense Perception’. In The Handbook of Atheistic Apologetics, I also justify (both pragmatically and deductively) logic, induction, the uniformity of nature, and moral responsibility.

    III. God is supposed to be at the center of everything, including our axioms (the god of the transcendental argument is the Creator of logic, for instance), but God is not a valid axiom. To be an axiom, a concept or proposition must fulfill three conditions:

    • It must be irreducible to prior concepts (i.e. foundational).
    • It must be self-evident to all acts of cognition (be they introspective or extrospective).
  • It must be undeniable without direct contradiction (committing the fallacy of the Stolen Concept).

    God does not share any of these attributes:

  • The concept of God is reducible to “immaterial consciousness”. Thus belief in God is not foundational.
  • The concept of God is not self-evident in my acts of cognition. When I look around, I see material objects having a definite nature. I do not see a god, or the effects of a god. It may be possible to prove by classical arguments that the effects of a god are present in nature, but it is not self-evident to me as an observer.
  • I can deny the existence of God without direct contradiction. When I state that “God does not exist”, I am assuming all the rational axioms (such as existence, identity, logic, consciousness, volition, and so on), but I am not assuming that God does indeed exist for me to able to say it. If the presuppositionalist is going to argue that I am indeed assuming that God does exist, he needs to prove it.

    Therefore putting God at the center of our foundational system is impossible, and we must reject (3) as a viable possibility. If God exists, it must be a deductive consequence of the axioms, not a source. Therefore God cannot be the creator of existence, consciousness, or logic, and we must also reject many X used in presuppositionalism.

    IV. The presuppositionalist reasoning lacks specificity. Even if we find that a creator of X (such as logic, consciousness, science, morality, meaning, and so on) is necessary, it must not necessarily be a god. Indeed, many pragmatists would not object in naming man as the creator of all these things. While this would make them conventions, and as I pointed out the rational worldview can justify these things perfectly, it is still a more reasonable and coherent position than (3).

    *V.* Even if we accept the entire transcendental argument, it does not prove that a god exists. All it proves is that Christianity has some kind of epistemic superiority. To make this clearer, we can express the conclusion of the argument as:

    1. Christianity is the only tool that can explain the existence of X.

      But this is not at all the same as:

      1. The Christian god exists.

      I can agree that (A) would be very problematic to the rational worldview, but it would not be problematic at all for atheism. Supposing once again that presuppositionalism is valid, it is entirely possible that Christianity is the only way we can make sense of epistemology, but that this is due to a flaw of our perception or linguistic constraints motivated by religious language. We could define Christianity, in that secular perspective, as an interpretative matrix that is quite independent of the claims of religious language. In this perspective, Christianity would not be true, but rather useful. The theologian would still need to prove that we should go from (A) to (B).

      VI. The crux of this argument is that the theological worldview explains the facts of human understanding better than materialism. But the only way theologians can do this, is by proposing that God wills these facts to obtain. If they cannot show that God wants logic, morality, meaning, to exist, then there is no reason for us to believe, even if we accept presuppositionalism, that God necessarily created these things.

      In fact, we should expect that an infinite god would not create anything at all, and it is clear that the god-hypothesis is falsified by the existence of the material world.

      I recently found a presuppositionalist article by James Anderson called ‘If Knowledge Then God’ (pdf). I was very delighted to find it, since it is a study of presuppositionalist arguments against the contrary. Seven arguments are presented, three from Plantinga and four from Van Til. I will go through each of these here.

      PLANTINGA ARGUMENT #1: The Evolutionary Argument against Naturalism

      This is a variant of (2b) above. I also address the argument specifically in my article ‘Cutting Off One’s Head: The Theological Attack Against Cognition’.

      PLANTINGA ARGUMENT #2: The Argument from Proper Function

      This is a variant of (2b), clarified by the term “proper function”. Basically, Plantinga argues that we can only have knowledge if our cognitive faculties have “a good design plan aimed at true-belief production”. It therefore can also be seen as a plain argument from design (pointing out “design” in the human brain and concluding God), and falls under the same problem, including the impossibility to prove that design is specifically needed.

      The equivocation between evolved instincts and individual epistemic methods that I discuss in my article can be seen easily here, if you read carefully. Plantinga is quoted saying as a requirement for warrant: ”(4) the design plan is a good one: that is, there is a high statistical or objective probability that the belief produced in accordance with the relevant segment of the design plan in that sort of environment is true”. But this assumes the absence of moral will, specifically of epistemic methods, hence the equivocation. This is a completely inadequate, invalid way of describing knowledge-acquisition.

      PLANTINGA ARGUMENT #3: The Argument from Anti-Realism

      This argument addresses epistemic anti-realism, entailing that reality is somehow subjective, a view which Plantinga rejects as absurd. I agree with him, but I am not an anti-realist.

      However, I also reject the claim that a standard of verifiability somehow entails metaphysical subjectivity. Science clearly does not entail metaphysical subjectivity despite its standards of falsifiability. Rather, it acknowledges the objectivity of reality, by demanding that our hypotheses be tested as to whether it conforms to the present or future evidence.

      VAN TIL ARGUMENT #1: The One-Many Argument

      The way Anderson presents this is extremely muddled. Basically, he seems to be asking how we account for concept-formation, but with long rambling paragraphs about “unity” and “plurality”, and how only Christianity posits that “unity” and “plurality” are “co-ultimate”.

      Objectivist concept-formation neatly destroys this argument (as far as there is one). To our senses, the existants we perceive exhibit both “unity” and “plurality” – they are all different but they all share basic material properties. Once again, the key here is materialism. The desk in front of me may be different from the pitcher of water, but they both have a shape, dimensions, colour, density, and so on.

      The process of measurement-omission consists of realizing, for instance, that there are a number of existants that have a flat surface and drawers, and that they are made to write on, or to support equipment. They may have different sizes, shapes, colours, number of drawers, and so on, but by “omitting” these “measurements”, I can integrate all these percepts into the concept “desk”. No nonsense about “unity” or “plurality” needed here.

      VAN TIL ARGUMENT #2: The Argument from the Unity of Knowledge

      I don’t really need to get into the whole argument on this one, since the first premise is bad enough: ”(20) If no one has comprehensive knowledge of the universe, then no one can have any knowledge of the universe”. Anderson justifies this premise by saying that, without comprehensive knowledge of the universe, a fact could come to light in the future to undermine any of our present knowledge. This is, therefore, a variant of (2c), and just as question-begging – in that atheism or knowledge does not imply belief in certainty at all.

      VAN TIL ARGUMENT #3: The Argument from the Uniformity of Nature

      Basically, the so-called “problem of induction”. I do intend to write a specific post on this topic eventually, but it looks like I should give the general lines of it now. Basically, it is the theist who has a “problem of induction”. Induction is based on the premise that our previous experiences are indicative of future ones. As I said in a previous post, if we accept the existence of miracles, then we must distrust our past experiences, and induction is impossible.

      The materialist, on the other hand, has no problem with induction. We know that we can trust our past experiences because we live in a self-contained (i.e. material) universe. There is nothing that can come and muddle the action of natural law on myself or my environment. I am perfectly comfortable knowing that the Sun will rise tomorrow, because the law of gravity will never be suspended. I have no epistemic anxiety whatsoever – but only because I am a materialist.

      VAN TIL ARGUMENT #4: The Argument from Conceptual Schemes

      In this argument, it is pointed out that human judgment is shaped by a number of presuppositions such as “logical principles, causal relations, metaphysical necessities, notions of self”. Anderson then asks whether 1. we can prove that the universe has such a relational structure and 2. how do we know that we understand the structure of the universe and 3. how do we know that everyone shares this knowledge.

      I can start with question 3, since it is ridiculously easy to answer: most of us share the same absolutes because they are part of the structure of our brain, and they are part of the structure of our brain because we could not reason or communicate without them. This is a straightforward consequence of evolutionary adaptation. Even the presuppositionalist shares the same absolutes we do, even if he denies some of them (such as materialism).

      How do we know the universe has this relational structure, and how do we know it? I don’t want to take too much space by justifying materialist metaphysics, although if there is any interest, I could address that at another time. All I’ll say is that the example of logic is particularly interesting, since Michael Martin has proven with TANG that Christianity is incompatible with any justification for logic. Therefore the presuppositionalist is left empty-handed yet again.

      Last updated: January 1, 2005