Sunday, June 09, 2019

The problem with TAG

I was asked to comment on this post:

I believe Alex Malpass is an atheist with a doctorate in philosophy. He's critiquing a version of presuppositionalism represented by Bahnsen and Butler. Certainly Michael Butler is several notches above the Syeclones. However, I think that's a fairly retro version of presuppositionalism. There are more promising versions. So that's not the version I'd defend. 

Talk of ‘the Christian worldview’ and ‘the non-Christian worldview’ is to be taken with a pinch of salt (although this will prove controversial later). Obviously, there are lots of different denominations of Christianity, including reformed Presbyterian, Lutheran, Catholic, Greek Orthodox, etc. Equally, there are many distinct non-Christian positions, including every denomination of every other religious worldview, plus every variation of atheist worldview, etc. 

In context, "the Christian worldview" is shorthand for Calvinism. Van Til was a Calvinist and his successors are Calvinists. And his Calvinism is not incidental to his position. In virtue of predestination and meticulous providence, everything happens for a reason. That's an essential component of presuppostionalism, in contrast to freewill theism or non-Christian worldviews where many events are pointless. This doesn't mean presuppositionalism requires Calvinism, per se, but it does require predestination and meticulous providence. In addition to Calvinism, other examples include the Augustinian tradition, classical Thomism, and Jansenism. Anything along those lines could lay a foundation for presuppositionalism. 

Here is my argument in a nutshell:

1. TAG is successful only if every non-Christian worldview necessarily entails a contradiction (or is ‘internally incoherent’).
2. There is a potentially infinite number of non-Christian worldviews.
3. Either:
4. a) There is one way to establish that all the non-Christian worldviews are internally incoherent, or b) One proof is not enough but there is a finite number of ways to establish that they are all incoherent, or c) There is an infinite number of ways required to establish that they are all incoherent.
5. No proponent of TAG has established a); and it seems easy to prove that b) cannot be established (given a plausible formalization of ‘worldview’ as a set of beliefs); and if c) then it is not possible for a finite being to prove TAG.
6. Therefore, TAG has not been established, and is likely to be unprovable.

That raises a raft of issues:

i) I don't see why TAG requires non-Christian alternatives to be self-contradictory. Why would it not suffice if non-Christian alternatives lack the explanatory power necessary to account for various things which a worldview should be able to ground? 

ii) Even assuming there's a potentially infinite number of alternatives, if many of these share a common flaw, than it's not necessary to disprove them individually. An argument that successfully targets a common flaw will automatically and simultaneously falsify every position that exemplifies that flaw at one stroke. That doesn't necessarily mean all the non-Christian alternatives share a common flaw. There might be sets of non-Christian alternatives that share common flaw, although one set exemplifies a different flaw than another. 

iii) The sweeping claim is not as brazen as it might appear to be. If a particular position is true, then all contrary positions are rendered false insofar as they conflict with the true position–although they may be true in other respects, or one contrary position might be true in a certain respect while another contrary position might be true in a different respect. For instance, metaphysics and epistemology in some Indian traditions might have different common flaws than conventional Western naturalism. 

iv) We could also recast the claim in hypothetical terms. It isn't necessary to dispatch every potential rival. Rather, show us what you've got. We're prepared to take on every comer. 

v) However, a nagging reservation remains. Since the proponent of TAG hasn't actually eliminated all the competition, how can he be justified in believing ahead of time that every non-Christian worldview will be self-contradictory or lack adequate explanatory power? TAG itself can't be the basis for his confidence inasmuch as TAG is untested against much or most of the competition. How does he know TAG is successful? He can't know TAG is successful in advance of using it to eliminate the alternatives, if the success of TAG relies on its proven ability to eliminate the alternatives. If you don't prove it in the field, what's the basis for your assurance that it will rout all the competition? So the proponent of TAG seems to need some other reason or reasons, independent of TAG, for believing the Christian faith is true, to warrant his prediction that TAG will be invincible against every contender. But in that event, TAG is a supplementary or confirmatory argument for Christianity, which takes its place alongside other arguments or prereflective evidence. I don't think that's a problem. But if that's the case, then TAG won't be able to replace other kinds of arguments or evidence for Christianity. 

One could put the point even more simply, as follows. The claim is that every non-Christian worldview is internally incoherent. If by ‘worldview’ we understand a set of propositions believed to be true by an agent, and by ‘internally incoherent’ we mean that the set is inconsistent (i.e. contains a proposition and its negation), then consider the non-Christian worldview that contains only one belief, i.e. {p}. This set is plainly not inconsistent. 

But that's artificial nonsense. There can be no worldview that contains only one belief. 

The retort will likely be that this ultra-simple worldview cannot ‘account for the intelligibility of human experience’. If so, what are the minimal conditions under which a set of beliefs could achieve this? It is not on the opponent of TAG to provide this analysis; all she has to do is point out that without this analysis the proof cannot be claimed to be established. The proponent of TAG needs to provide this analysis as part of the proof itself.

I agree with him that presuppositionalism can't shift the onus onto the unbeliever. Both sides have a burden of proof. 

In fact, it seems easy to prove that there cannot be one method which disproves every non-Christian worldview, because there cannot be one contradiction that they all share. 

That claim is far from self-evident. What reason is there to accept Malpass's assertion? Admittedly, I'd reframe the criterion in terms of explanatory inadequacy rather than self-contradiction. 

One natural way of understanding worldviews is that a worldview is just a list of propositions that an agent believes to be true.

There's a sense in which that's true. However, most folks aren't philosophers. Most folks aren't intellectuals. Most folks are pretty thoughtless when it comes to metaphysics, epistemology, and metaethics. Christian apologetics usually targets notable thinkers or schools of thought that make a concerted effort to think through their worldview, and not just what an unreflective individual happens to believe. 

[2]There are two objections here: 1) autonomy with respect to reasoning is not unique to the Christian worldview (what prevents other monotheisms from claiming that they also subordinate their reasoning to their god?), 

The question at issue is not what they claim but whether that's a demonstrable claim. 

and 2) there are Christian worldviews where the intellect is not subordinated to the word of God (there are autonomous Christian worldviews; in fact, almost all conceptions of Christianity apart from the Van Tilian presuppositionalist account do not explicitly subordinate the intellect to the word of God). So the equivalence of Christian worldview with non-autonomous reasoning fails in both directions.

i) That's hard to respond to because it's so vague. What does it mean to subordinate the intellect to the word of God? If Christian theism is true, then human reason is subordinate to divine reason, in part because divine reason is vastly superior to human reason, and because God is the cause of human reason. And the word of God exemplifies divine reason, making it the standard of comparison.

Perhaps what Malpass is gesturing at is the use of human reason to verify or eliminate revelatory claimants. Doesn't that subordinate the claimants to human reason?

ii) To begin with, if a revelatory claimant is not, in fact, the word of God, then evaluating a spurious revelatory claimant hardly subordinates the word of God to human reason.

iii) But suppose the revelatory claimant is the word of God? In that case, assessing the revelatory claimant doesn't necessarily subordinate the word of God to human reason inasmuch as God designed our minds, as well as the world we use as a frame of reference. To take a comparison, if the same locksmith designed the lock and the key, and I use the key to open the lock, I'm not subordinating the locksmith to the keyholder. Rather, I'm using what he handed me. I'm working within the framework I was given.  

iv) But that's complicated by the choice of criteria used to assess revelatory claimants. If truth is the criterion, then that doesn't subordinate the word of God to human reason, for human reason isn't the source of truth. Truth stands above human reason. 

Yet there's often a hiatus between truth and the perception of truth. The chosen criteria frequently degenerate into popular prejudice, tendentious standards, and glorified opinion rather than truth. The distinction or dichotomy between fact and what is deemed to be fact or allowed to be fact. 

v) In addition, the word of God has the authority to challenge and correct our preconceptions about reality and morality. So there's the tricky issue of how to make the transition from the standpoint of an outside observer sifting candidates to someone viewing the truth from the inside out. Perhaps there's no theoretical solution to this conundrum. It is up to God to place individuals far enough into the truth that they can see their way to the destination. 


  1. The other point that is not often considered is that instead of necessarily attacking opposing worldviews, TAG can be used to positively show that certain specific things would be required to make sense of some taken-for-granted human experience. So, for example, it could be argued that the only way that our senses can be considered sufficiently trustworthy to know the natural world--which we all believe--would be if those senses were created by an omni-deity who also wanted us to come to know of his existence and his divine attributes through the natural world. Now, such a view does not prove Christianity, but it does prove something like Christianity, and it is entirely consistent with the Christian view; it also certainly sounds like Christianity and Romans 1. Furthermore, in terms of the real worldviews on offer, it only matches Christianity. Thus, it would be rational to believe the Christian worldview on this basis. Granted, such an argument does not make Christianity certain, but it could make it believable beyond a reasonable doubt.

    This is in the same way that a Detective might examine a homicide scene and, based on the way that the woman was killed, determine that the murder could have only been committed by someone of exceptional/extreme strength. Of course, that would not prove with certainty that her cheated-upon powerlifting-champion of a husband committed the murder instead of all the other potential powerlifters/bodybuilders in the world, but since he is the only real contender in this case, then it would make it rational to believe that he was the culprit. The sort of reasoning is the same.

    Rad Miksa

    1. Pretty much Plantinga’s project in the Warrant Trilogy. Moral Arguments are similar IMHO.