On Presuppositionalist Apologetics

Posted by Alvin John Ballares | Posted on April 11, 2019

On Presuppositionalist Apologetics 

by Ben Sackenheim

Cincinnati, Ohio, United States

April 8, 2019

                  Many readers may not even be familiar with this term, but you will need to know it because if you are involved in the messy business of counterapologetics for long, you will eventually encounter it. Presuppositionalism is a drastically different method of apologetics from what has traditionally been practiced in the past 100, and even 15 years at time of this writing. But you had better learn how to deal with it, because it is going to turn up at some point, and if you have not studied it, you will likely not know how to handle it when it does.

                 So what is it? Presuppositional apologetics in Christianity is an apologetical method that presupposes the Christian god, and the Bible as his infallible word as the foundation for all other knowledge, and that without such a foundation, no one would be able to know anything. They use knowledge to mean absolute certainty, and they contend that without presupposing the Bible is true, one literally could not know anything including that one is not the only mind that exists or that one is not living in a simulated reality (two philosophical problems that are known formally as hard solipsism, and the Brain in a Vat problem, respectively). They further presuppose that everyone already has knowledge of the Christian god, and merely profess to disbelieve by suppressing the knowledge of god that they already have. They do not offer arguments and evidence to persuade people of god because that would be making man the judge instead of having god as the judge in their view.

                  Why is it as effective as it has been? It is a novel approach, much like a new chess opening such as Grob’s attack. It is effective not because it is logically valid, but because it is such a bizarre way to argue that those unfamiliar with it will not know how to counter it, just like how a pet opening in chess may surprise even an experienced player, but a sophisticated chess engine can show that even an opening that has won games is fundamentally broken or losing when the opponent plays correctly.

                  Presuppositionalism derives this novelty and surprise by exploiting what is unexplored territory for the vast majority of people: the foundations of logic itself. I would wager to say 99% of people live their entire lives making inferences, inductions, and deductions from an intuitive understanding of the Logical Absolutes, to include the Law of Identity, which states that A is equal to A, that something is what it is and it isn’t what it is not. Indeed, what a trivial thing to say. It is so trivial that practically no one would question why A is equal to A, and so when asked how one knows this to be the case, most people would have only a blank stare as a response. Presuppositionalists know this and try to paint a narrative that only theirs provides a foundation for having absolute certainty. “I have a foundation for knowledge where you can’t even know that you’re not a brain in a vat.” The Brain in a Vat Problem and the Problem of Hard Solipsism have long plagued philosophers for centuries. There is no known solution to these problems – they represent the limits of our knowledge, and philosophers are honest about this. Thus, someone claiming to be able to solve these problems would appear to have an advantage, though it doesn’t mean that they actually can solve these problems.

                  Before we can get into these problems and the reasons why philosophers can’t solve them, it is important to understand the motivation behind presuppositionalism. You are under no obligation to argue with a presuppositionalist, as their method is not about having an honest conversation. If you have to defend your position by calling into question the basic axioms of logic itself, you have gone horribly wrong somewhere. It is an interesting thought experiment to contemplate the foundations of logic, but then to use this as an argument for a patently absurd conclusion is dishonest in the extreme, especially when both parties in the argument already accept the laws of logic as being true in the first place. They are not trying to convince you or have a real dialogue; they are trying to shut down the dialogue and silence all legitimate criticism against their position, and they do so by calling into question something that almost everybody doesn’t know how to defend, so that they are met with a blank stare from which they will declare victory. I have spent much more time than I probably should arguing with presuppositionalists, and I know the conversation will never be resolved, because no matter what their opponent says, they can always respond “how do you know that?/Are you absolutely certain about that?/How do you know your reasoning is valid?” I have these conversations out of pure masochistic interest to examine and pick apart their arguments, even though I will never convince them of anything. What follows is what I have learned from such interactions.

                  Their enterprise is constructed from several pillars, but the one I wish to examine first is the idea that everyone actually knows that the Christian god exists, and those who profess to be non-believers are merely suppressing knowledge that they already have, in their own wickedness. They see this as a strength, but they do not realize that to everyone who does not believe, they have essentially proven their worldview to be false before we even examine everything else. I can’t prove to another person that I do or don’t believe in x, y, or z. But I can prove it to myself as I am the only one in a position to know what I do believe, what I do know, and conversely what I do not believe and do not know. When someone tells me that I know something that I do not know, they have shown to me that they are either lying or they are mistaken. Having dealt with this, it justifies the idea that I can know their worldview is false, and I could just stop and go on about my day. Everything else is just the icing on the cake, strategies for showing to others why their worldview is problematic, incorrect, and even dishonest.


                  The next thing to consider would be the way that they define knowledge as absolute certainty. People are free to use whatever definition they want for whatever word they want, and it is never wrong, it can only fail to reflect the most common usage. This is because words are merely tools to communicate ideas, and so the dictionary is not an authority on what a word means; there are no authorities on what a word means because words themselves don’t have meanings. We have meanings when we use words to convey them, according to a mutually agreed upon understanding. I beg the reader’s indulgence in this pedantry pageant, but it is necessary. The definition most commonly used by philosophers for “knowledge” is “justified, true belief.” This is also the definition that I use. Therefore in order to know something, there have to be true things in order to know, that it would be possible to believe those things, and that one has a justification for believing those things. Notice that none of these three require absolute certainty. Now a presupper reading this might be tempted to ask how I know that there are true things. However this is covered because “there are true things” must itself be a true thing, since if it were not true that there were true things, that would also have to be a true thing. In order for this not to be the case, logic itself would have to not be valid… this is where presuppositional apologetics leads. In order for them to have any case at all, it would have to be within the realm of possibility that logic were not valid. Let that sink in for a moment. Now of course presuppositional apologists do in fact accept the laws of logic as being true and valid. They just contend that they alone can justify it, where the rest of us have no foundation for believing logic is valid. But if they accept logic is valid for reasons that they think are justified, and we accept logic without having a good justification, it shouldn’t matter. So long as they accept logic, they should accept our conclusion that there are true things in this case, especially that they believe that god existing is a true thing, and they claim that we professing non-believers also know this to be true. I will deal with how one justifies logic more later on.


                  I just spent some time defending why knowledge need not have absolute certainty as a criterion for constituting knowledge. That being said, people are free to use whatever definitions they like, and if a presuppositionalist wishes to define knowledge as requiring absolute certainty, they are welcome to it. It just means that we are not talking about the same thing. But there is something more sinister going on here that often gets ignored. Presuppositionalists claim that god reveals things to them in such a way as to where they can be certain. But they miss the point that I can be absolutely certain about something, too. It just doesn’t guarantee in any way at all that what I am certain of is actually true. I have seen many debates involving presuppers, and I don’t recall this point being brought up. It is possible to be absolutely certain about something and still be completely wrong, so why should it matter to me whether or not they claim that they can know things with absolute certainty?

A Brain in a Vat

Brain in a vat

                  Almost every philosopher will tell you that it is impossible to know with absolute certainty that we are not living in a simulated reality, and there are even some philosophers who argue that we probably are in a simulated reality! Philosophers have gone on to show why it wouldn’t really matter if we were in a simulated reality. The fact of the matter is we have to deal with whatever reality we are presented, even if it is a simulation, until someone shows us a way to get out of the simulation. And even then, we would be faced with the same problem all over again, having to wonder if the reality we escaped into was also a simulation. As was just said, it doesn’t affect our lives in the slightest. From our perspective, the simulated reality is reality.

                  Presuppositionalists claim that if we cannot even know that we are not a brain in a vat, that we cannot know anything. The first thing to point out is that this is false; we can still know things that happen within the simulation if it is in fact one. Presumably, they fancy themselves able to know that they are not in fact brains in a vat, and that this information is revealed to them by an all-knowing god. In fact, they say that this is the only way they could know that they are not just a brain in a vat, if it were revealed to them by someone with perfect knowledge.

Dillahunty’s Dirty Water Filter

                  Matt Dillahunty, popular skepticism advocate a host of The Atheist Experience television show, counters this idea with an analogy of a dirty water filter. If you pour pristinely clean pure water through a dirty water filter, it doesn’t really matter how clean the water was when it went in, it is going to come out dirty. In the same way, even if it were true that there were an all knowing being with perfect knowledge, that wouldn’t change the fact that we do not have perfect knowledge, senses, or even cognitive faculties. If we did, there would be no presuppositional apologetics. So even if god imparts his perfect knowledge onto us, we still cannot fully trust our senses that we are in fact looking at perfect knowledge. It is not an issue with the software; it is an issue with the hardware. When a presuppositionalist asserts the Bible as the foundation for knowledge, and that it is the perfect infallible word of god, we can actually humor them by granting this to be true. It still remains the case that they have to rely on their own senses to know that the words in the Bible they are reading are actually there, and not just a hallucination.

Is God a Solipsist?

                  Everything up to this point has been showing why even an all knowing god couldn’t impart perfect knowledge with (justified) absolute certainty onto beings that themselves have cognitive flaws. Yet it turns out there is no reason to grant an apologist their assumption that god is all knowing. Not just because they merely define god as being all knowing without justifying how they know he is, but that there are reasons to think that it is in fact impossible for god to know everything, at least with absolute justified certainty. This would be the case if god couldn’t know that he is not a brain in a vat. It turns out this presents some very interesting ideas that apologists might not have considered.

                  Can god really know he isn’t in a simulated reality in which he is god? I contend no. If god is a conscious being, then that means there is a conscious experience of what it is like to be him, as that is what consciousness means. Presumably, god alone experiences what it is like to be him, and I think most religious people would agree with this. Yet if god is indeed all powerful, then it would be possible for him to upload that experience, complete with memories of having created the universe etc., onto another being, which would cause that person to be in a simulated reality in which he or she were god. That person would have no way of distinguishing between actually being god and merely being in a simulated such reality. And if this is the case, that god could do this to us, someone could have done this to god, and god would have no way of knowing. It is for this reason that the Brain in a Vat Problem functions very similarly to the mathematical operation of multiplying something by zero. (X)x0 = 0. Notice how it doesn’t matter what you put in the parentheses for X, it is always going to come out zero. So too for this.

                  Are there any valid objections to this line of reasoning? I have only seen two attempts ever given. The most common is the lazy way of just defining god as being all knowing. But this is question begging and circular. I just gave a reason for why god cannot in fact be all knowing, so to merely reassert that he is solves nothing. Remember, I can define god as a potato if I want to, but there is nothing about being able to define something in way x, y, or z that means one’s definition corresponds to anything that exists in reality. Define things however you like, as I said before, it doesn’t matter what you put into the parentheses. It isn’t the quality of X itself that creates or stops this problem. It is a characteristic of the operation itself of multiplying by zero, and the Brain in a Vat Problem is just something that goes along with consciousness, similarly.

                  The other objection that I have seen to this is that it isn’t possible for god to deceive someone since that goes against his nature. This is a rather creative way of trying to avoid the problem, but it is multiply problematic. It presupposes a Christian theological concept of god, that isn’t even necessarily Christian. Though modern Christian theologians often believe god can’t lie, the Bible does say otherwise. Exodus says that god hardens people’s hearts, Jesus says he speaks in parables to deliberately stop people on the outside from understanding, and 2 Thessalonians in context says:

                  …10and with every wicked deception directed against those who are perishing, because they refused the love of the truth that would have saved them. 11For this reason, God will send them a powerful delusion so that they will believe the lie, 12in order that judgment will come upon all who have disbelieved the truth and delighted in wickedness.…

            Of course presuppositionalists such as Sye Ten Bruggencate at this point will say “I don’t do Bible studies with atheists.” I’ll bet!

                  The other problem is that even if we accept that the Christian god would not deceive anyone, that would not solve the problem. The problem of the Brain in a Vat would remain because the Christian god could not know that he was not created in a simulated reality by a god who did not have the same traits. The real god, who in this thought experiment is deceptive, could say “I will cause you to believe that you are god while also imparting a trait to your personality that will preclude you from deceiving others.”

                  The last objection that I have seen is that obviously even with the simulations, there would still have to have been a real god to start the first simulation. While this is true, the whole point is whatever the actual god is, he too couldn’t know that there was not a reality outside of him for the exact same reasons we can’t.

The Foundations of Logic

                  Everything written so far is a reasoned critique of presuppositionalism, arguments for why such apologetics are vapid and unpersuasive, and reasons for why it just doesn’t represent good argumentation. The last section argued for why an all knowing being can’t exist, but it is not a deductive argument. The presuppositionalist can just dismiss any valid arguments against their position by saying “How do you know your reasoning is valid/How do you know that?” They will push things all the way back to the very foundations of logic. They are demanding a justification for things such as the Law of Identity, from which all the other laws of logic come.

                  The worst way that they try to demand a foundation for logic takes the form of Transcendental Arguments for God (TAG). They argue that because the laws of logic are immaterial and yet real, they need a transcendent cause for their existence. But this is no more than a reification fallacy, common among those who subscribe to the philosophy of platonic realism, the belief that abstract concepts like the number 4 and “blue” have a real existence. This is rejected by almost all philosophers today except for Christian apologists. Today in contemporary philosophy, it is understood that the number 4 isn’t something that just exists; it is a quantitative description of objects that do exist. Thus it is a category error. But the reason apologists love platonic realism so much is that it allows them to reify abstractions, bestowing upon them a real and contingent existence, and then demanding we show what caused their existence. This is a problem with their worldview though, not with mine. I have no obligation to show how the laws of logic exist if the laws of logic are not things that actually exist. The laws of logic don’t exist; they are ways of describing a reality which does exist.

                  But how about accounting for why the laws of logic are true? This is a much better question for a presupper to ask, since it commits no overt fallacy as in the paragraph above. The best I can do is try to provide a reasoned argument for why logic is valid, which I will do for the reader’s curiosity. It won’t matter to a presupper though, as they will say that I am using logic to prove the validity of logic, which is circular and illogical. I will deal with this after going into why logic is logical.

                  The Law of Identity is the law of logic from which we derive all other logic, reasoning skills, set theory etc. It simply states that A is equal to A, and A is not equal to not A. Said another way, something is what it is. What a trivial thing to say indeed! Where would we begin to defend this? Well, to suggest that we need a foundation for this, or a justification for why it is true, would imply at least a remote possibility that it could be false. What would that look like?

“A does not equal A.”

                  Utter this statement out loud. Before you have even gotten to the word “does”, you already said the word “A” and when doing so, you were referring to something. You had to refer to that thing with a concept of what it is you were referring to, in order to finish the sentence to say that thing was not what you were referring to. Because of this, for the law of identity to have a truth value of false, it would still have to be true first. That’s about as simple and straightforward of a justification as I can give, but it will never be enough for a pressupper, who will insist that I am using circular reasoning. After all, how silly of me to use logic to try to argue for the validity of logic. This would seemingly would surely seem to be an annihilating victory for them, yet ironically it ends up resulting in the complete destruction of the entire presuppositionalist enterprise.


The Achilles Heel of Presuppositionalism

                  Let’s grant the presuppositionalist the full force of his argument. I have utterly no foundation that I can use to justify why the laws of logic are true, and he is absolutely correct in this. I therefore have to presuppose that the laws of logic are valid, without any justification of them, in the same way that he presupposes god without any justification attempted. In the beginning of this writing, we saw that they are completely okay with the fact that they don’t have any justification for belief in god, that to try to justify this belief would be putting themselves as the judge instead of god. But if they allow themselves this liberty, they need to allow it to me. I presuppose the laws of logic are valid, and then derive all other knowledge from that presupposition.

                  This shows that the presuppositionalists do not have what they claim, an unconditional justification for absolute certainty; the presuppositionalist can justify absolute certainty only contingent upon their axioms being assumed to be true, mainly that a being with perfect knowledge can reveal things to them in such a way that they can be certain. But this tells us nothing about whether or not the axioms are in fact true. Everyone must presuppose the validity of logic in order to have a meaningful argument, but it may in fact be the case that my presupposition that logic is valid, is ultimately incorrect. I am more than happy to accept this. But likewise, the presuppositionalist cannot know that his presupposition is true. This position of not trying to justify that god exists because of a fear of putting themselves in the judge seat may or may not be morally virtuous according to their worldview, but as far as an argument goes, this is not a demonstration that they can’t be wrong; it is an unwillingness to consider that they could be wrong. And thus the idea that their original axiom, from which they derive all other knowledge in their worldview, could be completely mistaken remains an epistemic possibility.

                  This quickly devolves from being a matter of true or not true according to reality to being a matter of true or not true according to one’s worldview, via their axioms. We can debate all day about who’s worldview makes better sense out of the reality with which we are presented, but we cannot know with absolute justified certainty if it is actually true, irrespective of the context of any person’s worldview. Since we are now in the business of presupposing whatever we like as long as what follows from that doesn’t contradict our presupposition, someone else would be free to argue “I presuppose that I am right, therefore you are wrong.” Since we both know we can’t justify our presuppositions, mine actually stands on better footing because there are more ways for his presuppositional axioms to be wrong than mine. For all he knows, there could be a god who is deliberately deceiving him. Though “according to his worldview” god would not deceive, he cannot know this to be true, and if god were deceiving him, there would be no way for him to know it. He can only say “who am I to question god?” as has been said to me by a presuppositionalist I once had a debate with. Again, this constitutes nothing other than an abdication of responsibility to justify one’s worldview. By contrast, my presupposition that logic is valid could be mistaken, but I can rule out the potential for deliberate deception which they have to worry about. That is because logic is not a conscious agent capable of deception, but a proposed set of rules for how language and thought works. This renders my worldview more parsimonious than his.

Borrowing from my Worldview?

                  A core argument from presuppositionalists, and the way that they attempt to demonstrate that everyone believes in their god, is that the very concept of logic and truth presupposes the Christian god, and therefore everyone who uses logic and reason has to already accept that their god exists in order to argue against god, otherwise said “You are borrowing from my worldview.” I already showed why this is false, as I am well within my liberty to presuppose the validity of logic and reason as its own axiom, without needing or attempting to justify it. This is not a problem according to my worldview. It is rather their worldview that logic is derived from god’s nature, and so this would only be a problem with their worldview, just as that it is a problem with my worldview that they have no justification for god, but is not a problem with theirs.

                  But as my friend David Popiden noticed, all they are doing is trying to smuggle in a posteriori knowledge as if it were a priori knowledge. It is not the case that they take the Bible as true, and from that derive all other knowledge including that logic is valid and that they are not a brain in a vat. They must borrow from my worldview, presupposing logic in order to make intelligible sense out of the Bible! And not only that, but they have to presuppose the reliability of their own senses and that they are not the only mind that exists. Because if their whole worldview is based on the Bible being true, they have to first presuppose that the words they are looking at when they read the Bible are actually there in the first place, as was mentioned earlier in the Dirty Water Filter analogy. A fat lot of good it would do you to have a god reveal perfect knowledge to you in a medium that for all you know is just a hallucination.


                  This has been I hope a thorough analysis of presuppositionalist apologetics as practiced in contemporary Christianity. The only loose ends to tie up at this point are related to the issue of how to actually engage with presuppositionalists. I mentioned during the course of the analysis that in real-time, a presupper hearing any of this information would just interrupt and say “how do you know that/how do you know your reasoning is valid” before you even get to finish the sentence. As I said, it is about shutting down the conversation as quickly as possible in order to stop criticism of their pet belief system from coming up in the first place. Before engaging with this form of argumentation, remember the following points:

  • You are not obligated to have a conversation with someone whom you feel is not interested in an honest conversation.
  • You can know their position is false, even if you can’t prove it to them, when they make an incorrect claim about what you believe.
  • Someone can claim to be absolutely certain about something and still be completely wrong.
  • Presuppositionalists cannot demonstrate their initial axiom to be true any more than you can demonstrate that logic is valid.
  • Your presupposition of logic is a more parsimonious presupposition than theirs
  • God can’t be demonstrated to have perfect knowledge; he is merely defined that way, and there are good reasons to think he can’t in fact escape the Brain in a Vat Problem.
  • They must first presuppose that logic is valid and reality is real in order to get to a god belief or belief in god’s word via the Bible.

I encourage you to engage with presuppositionalists if you have the patience. Don’t expect a favorable outcome in terms of convincing them or having them admit defeat. They were probably going to try to declare victory all along. But engage with them to watch when they get confused when you take them off their script. We should actually appreciate them for helping us to consider things we never thought about, such as the foundations of logic. It may be the case that you encounter one who actually is an honest person, and is merely trying out a form of argumentation they heard before to see how it will be countered, just out of curiosity, and this has happened to me before. Be willing to accept an honest conversation if it does indeed become one. Good luck, have fun, and keep learning.

Other good reads...

How to Donate to HAPI

For those who have  paypal account please click the DONATE button on the right side or email funds to hapidonate@gmail.com For those without paypal account, We have  established a HAPI BANK for you: Account number: 006083-3810-41 BPI  Family Savings Bank- Vito Cruz/ Taft Avenue Account Name: Humanist Alliance Philippines International, Inc. For Local Bank Transactions […]

AHA surprise and books (HAPI- USA)

Ms M representing HAPI at AHA con 75th Anniversary, sporting the HAPI pin and AHA pin May 29, 2016, Chicago, IL – The American Humanist Association celebrated its 75th anniversary in Hyatt Regency hotel at McCormick Place on May 25-30, 2016. Our very own Founding Chairperson represented HAPI in Chicago, IL for the American Humanist […]

Fulfilling Dreams, Pt. 1: Bahay Pangarap

Angie Driskell June 18, 2020 Metro Manila 2020 was meant to be a year full of hope and accomplishments. It was a year I believed would become unforgettable… and it did, but for all the wrong reasons. I struggled to find alternative ways to reach out to those who may need help, or even just […]

HAPI’s 3rd BASIC Filipino Sign Language Class

The Meeting Plate, Pasay City, Metro Manila November 25, 2018 The Humanist Alliance Philippines International (HAPI) was again happy to wrap up yet another educational class opportunity to help those interested to learn Basic Filipino Sign Language. Now on its 3rd session, the class series aims to provide a very welcoming and open space for […]

How Humanism Gave Birth To Me

Vitruvian Man X Humanism

Humanism begins with a question I was 8 when I first pondered over the question, “Do cavemen go to hell?” This triggered me to question humans’ knowledge of the beyond, of what lies after we die. My thirst for knowledge led me to go on a philosophical adventure in search for “the truth”. Religion was […]

HAPI opens Filipino Sign Language classes to public

HAPI opens Filipino Sign Language classes to public

  Metro Manila Chapter of Humanist Alliance Philippines, International (HAPI) organized basic Filipino Sign Language (FSL) classes in light of the House of Representatives and the Senate approving the Filipino Sign Language Act. House Bill 7503 declares FSL as the national sign language of the Filipino deaf, and the official sign language of the Philippine government […]

“How HAPI Impacted Me” #1 – Shane Haro

How HAPI Impacted Me (#1) An essay series featuring retrospectives by HAPI members, staff, and leaders.   I cannot stress enough how humanism saved my life… or, at the very least, my worldview. Before coming across Humanist Alliance Philippines, International, I was a young atheist who wasn’t really sure where or whom to take his […]

About The Author

Ben Sackenheim

Ben Sackenheim is a specialist in counterapologetics who graduated from Defense Language Institute Foreign Language Center in Korean Studies, and holds a Bachelor of Arts in Organizational Leadership from Brandman University in Monterey California. An advocate of skepticism, epistemology, and humanism, he is also a performer of mentalism and theatrical mind reading.

Scroll to Top