# A Challenge to the Presuppositionalists



## no1special18 (Feb 16, 2009)

I wanted to pose a question regarding presuppositionalism in regards to logic. I believe that I am correct in saying that presuppositionalist say that logic cannot be supported by the unbelievers worldview. However, I am not sure that a theistic worldview is necessary to give an account of logic. My reasoning is that logic seems to be built on self evident laws such as A and not A. It seems obvious to me that one can self evidently perceive apart from the existence of God that my car is not both in my driveway and not in my driveway at the same time. Any thoughts?


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## Classical Presbyterian (Feb 16, 2009)

Total Depravity. We can twist whatever our sinful heart desires and call it "logic" when we are unregenerate. And we do!


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## no1special18 (Feb 16, 2009)

> Total Depravity. We can twist whatever our sinful heart desires and call it "logic" when we are unregenerate. And we do!



I agree that depraved man will twist logic, but as far as being able to account for logic from a worldview perspective, I believe that the unbeliever can give an account apart from appealing to theistic presuppositions.


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## Wannabee (Feb 16, 2009)

Simply put, without God there are no consistent laws, period; including laws of logic. Without God "A" has no meaning, let alone "not A." Such a position, in my opinion, is foundationally unstable and unsustainable.


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## Craig (Feb 16, 2009)

I could say anything is self-evident. It still doesn't prove anything.

Also, you may have never seen your car in your driveway and not in your driveway at the same time...does that mean it isn't (or hasn't been)?


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## Theognome (Feb 16, 2009)

One can be logical without being rational. You can take false premises and logically build conclusions from them. Obviously, such conclusions would be as or even more erroneous then the premises. An unbeliever building a world view upon false premises (atheistic) can draw logical conclusions that are utter nonsense. Rationality of worldview can only be achieved through theistic thinking, for therein lies true premises.

Theognome


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## MW (Feb 16, 2009)

no1special18 said:


> My reasoning is that logic seems to be built on self evident laws such as A and not A.



These self-evident laws are a part of the presupposed framework within which humans reason. Are they applicable everywhere, at all times, and under all conditions? If so, then there must be an infinite, eternal and unchangeable Mind which validates them. If not, then they are not self-evident laws, but mere temporary conventions.


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## no1special18 (Feb 16, 2009)

> I could say anything is self-evident. It still doesn't prove anything.
> 
> Also, you may have never seen your car in your driveway and not in your driveway at the same time...does that mean it isn't (or hasn't been)?





> These self-evident laws are a part of the presupposed framework within which humans reason. Are they applicable everywhere, at all times, and under all conditions? If so, then there must be an infinite, eternal and unchangeable Mind which validates them. If not, then they are not self-evident laws, but mere temporary conventions.



You could not accurately say all things are self evident. 2 plus 2 equals four because once the nature of 2 and addition are understood then they must equal four, hence it is a self evident truth. Once the nature of something being and not being is understood then A and not A have to be self evident laws. Also, it is part of the very nature of self-evident laws such as 2 and 2 equal four to be applicable everywhere and for all time.


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## Craig (Feb 16, 2009)

no1special18 said:


> You could not accurately say all things are self evident.



Says who? I say it's self-evident that cold baths kill people. I saw a man step into a bath tub, lay down, then grabbed a hairdryer that was plugged into the wall. I knew the water was too cold because he shook himself to death.



no1special18 said:


> 2 plus 2 equals four because once the nature of 2 and addition are understood then they must equal four, hence it is a self evident truth. Once the nature of something being and not being is understood then A and not A have to be self evident laws. Also, it is part of the very nature of self-evident laws such as 2 and 2 equal four to be applicable everywhere and for all time.



You're assuming there's a relationship between numbers...you would be begging the question as you're establishing order by first assuming it is the case. As Rev Winzer has pointed out, that may only be a convention...true now, but maybe not in 5 seconds. I see change all day long...especially after many years...if anything, it is self-evident that all things change. It should be self-evident that there are no fixed laws of logic.


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## MW (Feb 16, 2009)

no1special18 said:


> 2 plus 2 equals four because once the nature of 2 and addition are understood then they must equal four, hence it is a self evident truth.



Have you been everywhere all at once to know that it is a self-evident truth? There may be some place somewhere in which it is not self-evident. You are making an assumption about the regularity of the human condition which you are unable to personally validate. In other words,, you are assuming the Christian view of man in a created universe in order to state what you consider to be a fact.


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## Zenas (Feb 16, 2009)

The self-evident laws of logic make it impossible for the non-theistic framework to work. A book has an author, a painting has a painter, and logic has its Logistician. The very laws the unbeliever appeals to in order to make their argument for the non-existence of God provides the noose to hang them with-they have to account for its existence somehow, it cannot be self-evident because it does not allow itself to be.

The laws of logic say that ex nihilo nihil fit, i.e. there is no self-creation from nothing. The laws of logic also say that A cannot be both A and non A at the same time in the same place, ergo the Universe cannot create itself. The non-believer has to answer these questions that logic bears, and they are unable to. 

Even assuming that logic is self-evident and woven within the fabric of the Universe itself, it still must ultimately have a Creator.


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## Whitefield (Feb 16, 2009)

armourbearer said:


> In other words,, you are assuming the Christian view of man in a created universe in order to state what you consider to be a fact.



I think that was Van Til's point when he used the example of a young girl he saw on a train who slapped her father's face while sitting on his lap.


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## Theognome (Feb 16, 2009)

*sigh*

You can't win. Logic can be built from _anything_, but truth can only be given through faith. No one can logically pinpoint theistic thinking, for it is a gift of the Holy Spirit, and has not its origins in man. This thread will, unfortunately, go nowhere.

The strength of Presuppositionalism is the acknowledgment of this very fact- man, outside of regeneration, can only build upon irrational premises that are based upon a rebellious state. The logical conclusions of guilty man _will always be in error_. No amount of logical wrangling will ever fix this, and to try to make sense of it is to play the role of God. This is the mystery Paul spoke of- that we, as fallen beings, are given a true, rational Rock upon which to build our thinking. If anything, we should tremble before this truth, and pray for the furtherance of the Gospel of Jesus Christ into the world of the unrepentant.

Theognome


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## davidsuggs (Feb 16, 2009)

The problem with the term "self-evident" is clearly underlying the context of this discussion. "Self-evident", or even "evident" for that matter, is only concerned with the subjective perception of an individual. Many things may _appear_ self-evident to me without being grounded in fact. Greg Bahnsen never had a problem with using the term but I do and Van Til commonly veered away from it also, forsaking it for "necessity". A necessary truth is one that is true in all possible worlds (as opposed to a contingent truth, which is true in at least one possible world). God Himself is necessary and cannot not exist. Logic, being contingent upon Him, is thus also necessary, but ONLY because of His unchanging character. Hence, logic cannot not exist, but that truth only makes sense at all because logic itself is a quality of God, not some reified principle existing somewhere in the abstract universe. The Christian worldview, being the only one to accurately hold the fundamental character of God and all of His attributes, is the only one which can account for the existence of logic and ordering of our world, including logic which is imposed upon the human mind by God when He created us in _imago Dei_.


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## kalawine (Feb 17, 2009)

davidsuggs said:


> The problem with the term "self-evident" is clearly underlying the context of this discussion. "Self-evident", or even "evident" for that matter, is only concerned with the subjective perception of an individual. Many things may _appear_ self-evident to me without being grounded in fact.



 The term "self-evident" is practically useless. It's reminds me of the term "common sense." (Though they don't mean the same thing) For centuries it was "common sense" that the earth was flat. 

Who is the "self" that "self-evidence" is evident to? And what is "evident" to you may not be evident to "my-_self_"

Would someone grab my hand and pull me out of this fog?


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## MW (Feb 17, 2009)

There are some things without which nothing would be evident -- these are self-evident truths according to the philosophy of common sense realism. They are not subjective and limited to one viewpoint, but true in all conditions of human thought.


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## kalawine (Feb 17, 2009)

armourbearer said:


> There are some things without which nothing would be evident -- these are self-evident truths according to the philosophy of common sense realism. They are not subjective and limited to one viewpoint, but true in all conditions of human thought.



Hmmm... that's new to me. Would you mind telling me more about "the philosophy of common sense realism?" I am a Presuppositionalist but I've never believed in common sense. The only thing I know of without which nothing would be evident is logic. Do I have the wrong idea about that?


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## Roldan (Feb 17, 2009)

no1special18 said:


> I wanted to pose a question regarding presuppositionalism in regards to logic. I believe that I am correct in saying that presuppositionalist say that logic cannot be supported by the unbelievers worldview. However, I am not sure that a theistic worldview is necessary to give an account of logic. My reasoning is that logic seems to be built on self evident laws such as A and not A. It seems obvious to me that one can self evidently perceive apart from the existence of God that my car is not both in my driveway and not in my driveway at the same time. Any thoughts?



in my opinion, I think your confusing the fact that humans can reason with the notion that atheist can't account for this reasoning. Presuppositionalism doesn't say atheist don't use logic or reason because as you stated obviously they do and do so at the same time denying that God exist BUT the problem is that by denying God they contradict themselves and become irrational so that at the same time they are logical and illogical, go figure. So therefore an atheist can reason but cannot account for their reasoning.

Maybe you already knew that but I just thought I share


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## JohnGill (Feb 17, 2009)

no1special18 said:


> I wanted to pose a question regarding presuppositionalism in regards to logic.
> 
> (1) I believe that I am correct in saying that presuppositionalist say that logic cannot be supported by the unbelievers worldview.
> 
> ...



1) Logic does not make sense outside of the non-christian worldview. Atheists are able to think logically, but their worldview does not account for this. 

2) Provide an alternative worldview which gives an account of the laws of logic.

3) Self evident to whom? Which kind of logic? Who determines what is and what is not self evident? Who determines what is and what is not logical? Either the laws of logic are a reflection of God's thinking or they are arbitrary and therefore meaningless.

4) Without the Christian God you have no class concept of car, driveway, not, and language and therefore could not state anything about your perceptions. Or to put it another way, apart from the existence of God your experiences are meaningless.


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## MW (Feb 17, 2009)

kalawine said:


> Hmmm... that's new to me. Would you mind telling me more about "the philosophy of common sense realism?" I am a Presuppositionalist but I've never believed in common sense. The only thing I know of without which nothing would be evident is logic. Do I have the wrong idea about that?



Please consult the introductory article, "Scottish Realism," by D. F. Kelly in the Evangelical Dictionary of Theology. It is available online here: Scottish Realism and Scotism.


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## kalawine (Feb 19, 2009)

armourbearer said:


> kalawine said:
> 
> 
> > Hmmm... that's new to me. Would you mind telling me more about "the philosophy of common sense realism?" I am a Presuppositionalist but I've never believed in common sense. The only thing I know of without which nothing would be evident is logic. Do I have the wrong idea about that?
> ...



Thanks! I will!


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## Confessor (Feb 19, 2009)

I have been doing some personal work on this subject, and by God's grace I believe I have made some great strides.

To put it briefly, the atheist can be absolutely correct when he mentions the axiomatic nature of logic. He is completely correct when he establishes that logic is self-evident and cannot possibly be denied.

...but it doesn't follow that any worldview is _justified_ in holding logic, as some type of coherence still has to be demonstrated between the unbelieving presupposition and this established fact of logic. He still _has_ to have a presupposition, and as he could later find out in some argumentation, the _characteristics_ of logic (i.e., its universality and prescriptiveness) cannot possibly be reconciled with his presupposition.

The most important thing to do if an atheist brings up this objection is tell him that he is correct that logic is self-evident -- now how does it fit into his worldview? He has explained the characteristics of it, but he hasn't begun to say how that actually fits into his worldview.


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## Brian Withnell (Feb 19, 2009)

*We cannot escape our own world view*

First, I am presuppositional in my theology, and I hold that the universe in which we live is in fact correctly viewed only through the lens of scripture and the illumination of the Holy Spirit. I hold that the only universe that could exist is the one that God created, because I hold that God does exist as he has revealed himself.

That said, I would want to state something I do not believe is true, but at least is consistent from the standpoint of logic.

Suppose logic is an inherent property of the universe. Not that it is caused by anything or that anything could change universal consistency, but just that these are properties of an eternally existent universe (I know, that is a rather large pill to swallow, but remember, I don’t believe it for a heartbeat either).

Now what do you have? Logic is possible, and can be consistent without a presupposition of a God that causes consistency. That flies in the face of what we as believers know to be true, but from a logical standpoint, if those properties required for logic just happen to be part of the universe, then it just is.

We cannot escape our worldview any more than the unregenerate could escape their world view without the regenerative power of the Holy Spirit.

The real issue though is not that they could be consistent. That is beside the point. The Bible says they know the truth because God has made it known to them. Nobody doesn’t believe in God because they don’t have enough evidence; people do not believe because they know who God is, and hate him. We should not be surprised that the world hates God; Jesus said “If the world hates you, you know that it has hated Me before it hated you.” (John 15:18 NASB) The world denies God because it hates God and for “good reason”: God is the thrice Holy, Righteous Judge who will not pardon the guilty; He will bring justice, which is condemnation to the world.

Because our eyes have been opened, we no longer have a perspective of being blind. We no more could see the universe without God than we could have a heart of stone if God has given us a heart of flesh.


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## MW (Feb 19, 2009)

Brian Withnell said:


> Suppose logic is an inherent property of the universe. Not that it is caused by anything or that anything could change universal consistency, but just that these are properties of an eternally existent universe (I know, that is a rather large pill to swallow, but remember, I don’t believe it for a heartbeat either).



Does this eternally existing universe possess a Mind then?


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## Confessor (Feb 25, 2009)

armourbearer said:


> no1special18 said:
> 
> 
> > My reasoning is that logic seems to be built on self evident laws such as A and not A.
> ...



Be careful not to argue evidentially with premises such as these. It is not our goal to try to build our case from the ground up and say, "Logic demands an infinite mind; therefore, Christianity is true" -- because 1. that presupposes a self-existing framework apart form God (since we did not explicitly presuppose Him from the outset), which is to deny His sovereignty and idolatrously prefer a separate worldview, and 2. such an argument would never possibly work, for it is a _non sequitur_ to jump from the premise "an eternal mind exists" to the conclusion "Scripture is true," even if deism and all other revelational religions have already been refuted in some other way. We have to _start_ with Scripture.

...and if you implied this entire methodology in your statement without explicitly saying so, then I apologize for essentially preaching to the choir.


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## Brian Withnell (Feb 25, 2009)

armourbearer said:


> Brian Withnell said:
> 
> 
> > Suppose logic is an inherent property of the universe. Not that it is caused by anything or that anything could change universal consistency, but just that these are properties of an eternally existent universe (I know, that is a rather large pill to swallow, but remember, I don’t believe it for a heartbeat either).
> ...



It wouldn't have to, it would only have to have logic as one of the inherent properties.

It is *really* difficult to get outside of my own view ... but what I tend to do with these things is remove the axioms I hold true, and then figure out what axioms would be necessary without my axiom set. It is painfully difficult, because I *know* it isn't what anyone actually lives by (nobody really believes it) but I also know that some are so blind that they talk it as if they did.


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## Confessor (Feb 25, 2009)

Brian Withnell said:


> armourbearer said:
> 
> 
> > Brian Withnell said:
> ...



It is perfectly acceptable to let the unbeliever say that logic is "inherent in the universe" or whatever, because logic is axiomatic. _Unbelievers are perfectly justified in believing in axiomatic truths_. However, it does *not* follow that these truths which they believe are consistent with their previously chosen presuppositions.

For instance, before a person can even begin to reason with logic, he must first view the laws of logic as either an entity under God's sovereignty, or a self-existent entity apart from God's sovereignty. There is no middle ground. At this point, he can choose a Christian presupposition or an anti-Christian one.

If he chooses the anti-Christian one (we'll assume generic atheism for demonstration's sake), then he has just affirmed the lack of a providential Organizer of the universe and the lack of a universal Judge. Seeing as laws of logic (which he already believes and is justified in believing because they are axiomatic) are _universal_ and _prescriptive_, it follows that his presupposition is inconsistent with his belief in the law of logic.

Thus, he is not wrong in believing in logic; he's wrong in thinking that he can believe in whatever presupposition he's holding. Hopefully this will make him come to repentance, seeing as he is utilizing a concept which doesn't make sense with his presupposition, yet he used the concept sensibly.  But only God can make the unbeliever identify the grace of God at work and accept it in faith.

So basically, the general rule for arguing this way is not to argue for the sheer _existence_ of axiomatic truths -- since everyone, per the definition of "axiom," is epistemically justified in believing in them -- but rather for the _characteristics_ of these truths, and showing how they do or do not comport with the unbeliever's presupposition.


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## MW (Feb 25, 2009)

Confessor said:


> that presupposes a self-existing framework apart form God (since we did not explicitly presuppose Him from the outset), which is to deny His sovereignty and idolatrously prefer a separate worldview, and 2. such an argument would never possibly work, for it is a _non sequitur_ to jump from the premise "an eternal mind exists" to the conclusion "Scripture is true," even if deism and all other revelational religions have already been refuted in some other way. We have to _start_ with Scripture.



I'm not sure how you arrive at point 1. A presupposition is not something thought up out of thin air, but that which can be proven to be a precondition of rationality. One must be able to provide a rational account for their starting point in order to counter a charge of irrationality. This is not evidentialism since it does not argue from evidence to fact, but simply provides the theoretical basis upon which the facts can be accounted for.

Point 2 is easily rebutted by keeping in mind that a precondition for human rationality is not only the eternal Mind validating all facts but also the realisation that there could be no knowledge of any fact unless that eternal Mind revealed Himself.


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## MW (Feb 25, 2009)

Brian Withnell said:


> It wouldn't have to, it would only have to have logic as one of the inherent properties.



Logic requires a thought process whereby one moves from antecedent to consequent. If this so-called eternal universe has no thought process then logic cannot be inherent within it. In order for there to be logic in this universe there must be a Mind in which the antecedent and the consequent are validated.


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## Zenas (Feb 25, 2009)

armourbearer said:


> Brian Withnell said:
> 
> 
> > It wouldn't have to, it would only have to have logic as one of the inherent properties.
> ...



You beat me to it. This just dawned on me and I was about to post something to this effect, though not as concise.


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## Confessor (Feb 25, 2009)

armourbearer said:


> Confessor said:
> 
> 
> > that presupposes a self-existing framework apart form God (since we did not explicitly presuppose Him from the outset), which is to deny His sovereignty and idolatrously prefer a separate worldview, and 2. such an argument would never possibly work, for it is a _non sequitur_ to jump from the premise "an eternal mind exists" to the conclusion "Scripture is true," even if deism and all other revelational religions have already been refuted in some other way. We have to _start_ with Scripture.
> ...



As Christians (actually, as humans), we do not have a rationalistic approach to our worldview. We don't reason _towards_ the truthfulness of Scripture. Scripture is truthful from the outset, and we know that it is not because we've figured it out in some other manner, but because the Holy Spirit Himself has opened our eyes to accept it as a pre-rational authority. Scripture is the ground of _all_ reasoning and not merely the conclusion of metalogical reasoning.

In fact, the methodology of trying to find out which authority is correct is a flaw which Van Til pointed out in Francis Schaeffer's (I think) apologetic, for doing so presupposes that there is some authority external to the one for which we are searching, and from which we can reason in the first place. If we try to say the Bible is not necessarily true and "neutrally" attempt to find out what is a necessary precondition of intelligibility, then we are assuming that a separate framework is possible from which we can neutrally reason, and that the Bible is not _completely_ necessary.

So, in other words, because of the Holy Spirit's witness, we do in a sense obtain the presupposition of Scripture out of thin air. We start with it before even reasoning in the first place. We still have a rational account for holding this presupposition, but not for _arriving_ at it, because by definition we must _start_ with it. And if we don't _start_ with our presupposition, then we are trying to lay the groundwork for rationality is a purportedly neutral fashion, which is in fact _evidentialism_, albeit an uncommon variance of it.



armourbearer said:


> Point 2 is easily rebutted by keeping in mind that a precondition for human rationality is not only the eternal Mind validating all facts but also the realisation that there could be no knowledge of any fact unless that eternal Mind revealed Himself.



But, again, this does not establish the Bible's authority, even if all other revelations (e.g. the Qur'an) are disproven. This is true because, in such a case, we are still saying that the Bible is God's Word iff it passes a test for us humans (_viz._ that we find it to be consistent), and iff it remains rationally appropriate for us humans. If there is some methodology which does not _necessarily_ have Scripture's veracity as its basis, then Scripture cannot be as authoritative as it ought to be -- for in that case whatever methodology was used to arrive at the conclusion "Scripture is true" is in fact more authoritative than Scripture itself.

Moreover, a nonbeliever could legitimately claim, after being confronted with this argument, that whatever appropriate revelation there was is now gone. Why not the revelation of the Mayans or the Incans? Why not some Eastern religion whose text we have lost in the annals of history? If we establish the necessity of revelation, and even if we establish the Bible as consistent, this still leaves plenty of (rational) safety valves for unbelief.

I'm not saying it's wrong to argue for the fact that revelation is needed. That is still an awesome argument to use. However, once we establish the necessity of revelation, we should not view this as some "neutral" fact from which we can move to Scripture. Rather, we show how the starting point of Scripture accords with this fact (of the necessity of revelation), and how the unbeliever's starting point adamantly does _not_.

In other words, the argument for the necessity of revelation is a "primary interpretation" as I espouse in this thread. I have, however, changed my current terminology to "immutable fact" rather than "primary interpretation," because the former term fits the concept much better than the latter does. The last post in that thread makes note of this modification.


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## Brian Withnell (Feb 25, 2009)

armourbearer said:


> A presupposition is not something thought up out of thin air, but that which can be proven to be a precondition of rationality. One must be able to provide a rational account for their starting point in order to counter a charge of irrationality. This is not evidentialism since it does not argue from evidence to fact, but simply provides the theoretical basis upon which the facts can be accounted for.



I can tell you are no mathematician. 

If you have that a presupposition is what can be proven as a condition of rationality, then what you are left with is rationality is the presupposition and all else is theorem. Not only that, but many rational systems would be excluded as the axioms of the system would not be provable as necessary.

Presuppositions are statements taken as true without proof. Irrationality can only be charged against a system of presupposition which lead to contradiction. Thus strong geometry (those that have no parallel postulate or one of the alternatives) are rational, but that does not mean that either Euclidean geometry or elliptical geometry are irrational. The Euclidean parallel postulate is not required for rationality (every time I step on an airplane I trust the pilot to have done his navigation via spherical geometry, a subset of elliptical geometry, which contradicts Euclidean geometry at the level of presupposition).

Presupposition in any field is fairly straight forward ... it is taken as true without proof. That does not mean there cannot be reason for thinking it true. The example of elliptical geometry came out of attempting to prove the parallel postulate from the other Euclidean postulates ... until a model for elliptical geometry in the real world was mapped to the geometry. The real world has no contradictions (thanks to the God who designed it), so discovering model for the real world in elliptical geometry proved it is without contradiction.

Presuppositions are the foundation we set for a logical system. While as Christians, we know there is a foundation that models the universe appropriately, it is not impossible to have a set of axioms that say nothing of the real world (pure mathematics does it all the time). What is significant in one sense is that we know those that oppose our system of presuppositions _cannot do so consistently with their lives._ Those that want to borrow morality have to presume a basis for it. Not only that, but they know the truth, because God has made it known to them, and God created them with a conscience that either excuses them or accuses them based on conformity to our foundation (at least when they have not had their conscience seared by long practice of suppression the truth in unrighteousness).

-----Added 2/25/2009 at 10:05:38 EST-----



Confessor said:


> If he chooses the anti-Christian one (we'll assume generic atheism for demonstration's sake), then he has just affirmed the lack of a providential Organizer of the universe and the lack of a universal Judge. Seeing as laws of logic (which he already believes and is justified in believing because they are axiomatic) are _universal_ and _prescriptive_, it follows that his presupposition is inconsistent with his belief in the law of logic.



Hmmm.... I'm not sure what you are intending that the axioms which he holds are universal and prescriptive. That the universe is logical (as an inherent trait) does not seem to (at first blush) mean that it must have additional axioms which are universal and prescriptive. In my prior post to Matthew W. I stated that two axiom sets are operative and without contradiction in different geometric spaces. I'm not sure why what you are saying requires some different "universal and prescriptive" when in our day-to-day lives, we can have different logical systems.

-----Added 2/25/2009 at 10:19:09 EST-----



armourbearer said:


> Brian Withnell said:
> 
> 
> > It wouldn't have to, it would only have to have logic as one of the inherent properties.
> ...



I would respectfully disagree. Moving from antecedent to consequence is causality, not logic. I see no reason for either to be validated in order to exist. If they just are, there is no need for validation ... of course if you are talking about there needs to be a way of mapping the axiom set to a model of the universe (model validation) then either mapping or not mapping is irrelevant to the logic of the model. There are mathematical models for which no map has been found and for which none are sought. Validation from the standpoint of proving non-contradiction is not required for logic, though it would be required that presuppositions that are contradictory be labeled illogical. People examine them for years upon years without finding a model or a contradiction. Are they logical? From the standpoint of being based on a set of axioms, undefined and defined terms, and built upon them -- yes, they are logical. Are those systems validated? A pure mathematician would only care in as much as if they were, they might move on to some other system that is still within abstraction.


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## MW (Feb 25, 2009)

Brian Withnell said:


> I would respectfully disagree. Moving from antecedent to consequence is causality, not logic. I see no reason for either to be validated in order to exist.



Then the "causality" is a rational observation. Again, this is not something inherent in the universe, but something mind abstractly works with.


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## MW (Feb 25, 2009)

Confessor said:


> Scripture is truthful from the outset, and we know that it is not because we've figured it out in some other manner, but because the Holy Spirit Himself has opened our eyes to accept it as a pre-rational authority.



How do you know that it is the Holy Spirit who opened your eyes to Scripture and not some other spirit? There must be marks whereby this can be ascertained to be genuine. The marks are not the cause for the belief but are a consequence to be expected if this is a true work of the Holy Spirit. One is not at liberty to say, The Holy Spirit told me so, and leave it at that; the Bible requires us to "prove all things."


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## Confessor (Feb 25, 2009)

Brian Withnell said:


> That the universe is logical (as an inherent trait) does not seem to (at first blush) mean that it must have additional axioms which are universal and prescriptive.



No, I'm saying that the axiom of logic, i.e., "the laws of logic are true," _contains_ the characteristics of logic, and these characteristics are universality and prescriptiveness. It would make absolutely no sense for an atheist to say he believes in the laws of logic but not in their universality or their prescriptiveness. They are objective, not conventional. Thus, he must show whether or not his presupposition is consistent with these characteristics that he is _obliged_ to accept contained in the axiom.

Also, just so I can learn some more stuff pertaining to axioms, what specifically are the axioms of different types of geometry? What propositions are they?

-----Added 2/25/2009 at 10:39:48 EST-----



armourbearer said:


> How do you know that it is the Holy Spirit who opened your eyes to Scripture and not some other spirit? There must be marks whereby this can be ascertained to be genuine.



This is the thinking that denies presuppositionalism in the first place. "You can't do that; you must prove it by some other means." No, I simply do _not_ have to appeal to a higher authority to validate any work of God. You may ask how I know it is a work of God, but the answer is that I simply _know_ it. If I had to make it accord with a higher authority, then God would not retain any authority. His witness is infallible, and I don't have to "prove" its infallibility; that is an absurd concept.

The best feeling I can explain which can objectify the subjectivity of the experience is this one: imagine you are in an argument with someone, and at some point (maybe after you've heard a point he just made), you are completely assured that you are correct -- you _know_ you are correct -- but this assurance occurs before you actually formulate your argument. Of course, as the argument pans out, you formulate your argument and end up beating the other guy down, meaning that you had some legitimate knowledge _prior _to an actual rational undergirding for it. There did end up being a correct rational basis, but nonetheless you had correct _knowledge_ before even thinking of this basis. It is likewise with Christians and the Holy Spirit and the obvious witness of Scripture.

While this may sound unfair, please recognize that I am still willing to demonstrate the consistency of my worldview and offer a full apologetic, but I am not doing this as if I expect to find any sort of flaw in mine, because I already have a completely true and convincing knowledge that such an occasion would be impossible. In fact, it would be _illogical_ for me to expect any type of possible flaw in the first place, but I still am completely willing to demonstrate this flawlessness. Thus, certainty of the faith and fairness in apologetical argumentation are still balanced, and this is done by none other than God Himself, the Holy Spirit.



armourbearer said:


> One is not at liberty to say, The Holy Spirit told me so, and leave it at that; the Bible requires us to "prove all things."



Actually, to appeal to the work of God as proof would be objectively sound, but it would lack any persuasive ability. Apologetics consists of this persuasion.

This, by the way, is why not every Christian who can think through the most intricate philosophical implications of belief is still epistemically justified in his or her belief in God, and why every person on Earth is epistemically _obliged_ to believe in God. From the outset, everyone's _sensus divinitatus_ makes God-belief obligatory. Submission to God is demanded prior to any reasoning, even reasoning to find out what our authority should be, which was (partially) the sin of Eve.


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## MW (Feb 25, 2009)

Confessor said:


> This is the thinking that denies presuppositionalism in the first place. "You can't do that; you must prove it by some other means." No, I simply do _not_ have to appeal to a higher authority to validate any work of God. You may ask how I know it is a work of God, but the answer is that I simply _know_ it. If I had to make it accord with a higher authority, then God would not retain any authority. His witness is infallible, and I don't have to "prove" its infallibility; that is an absurd concept.



You are answering a figment. I have distinguished between evidentialism which proves and a presuppositional approach which confirms faith. If you cannot show how your Christianity confirms your presuppostional belief in the authority of Scripture then you are asking me to disbelieve the Bible when it tells me to discern teachings by their fruits.


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## Confessor (Feb 25, 2009)

armourbearer said:


> You are answering a figment. I have distinguished between evidentialism which proves and a presuppositional approach which confirms faith. If you cannot show how your Christianity confirms your presuppostional belief in the authority of Scripture then you are asking me to disbelieve the Bible when it tells me to discern teachings by their fruits.



It appears that this previous paragraph of mine answers your request.

"While this may sound unfair, please recognize that I am still willing to demonstrate the consistency of my worldview and offer a full apologetic, but I am not doing this as if I expect to find any sort of flaw in mine, because I already have a completely true and convincing knowledge that such an occasion would be impossible. In fact, it would be illogical for me to expect any type of possible flaw in the first place, but I still am completely willing to demonstrate this flawlessness. Thus, certainty of the faith and fairness in apologetical argumentation are still balanced, and this is done by none other than God Himself, the Holy Spirit."

I'm not saying apologetics should consist of our telling unbelievers to look inside themselves, and look inside themselves further, and they just haven't heard the right Spirit, etc. Although that may be true, that is not apologetics. But it doesn't follow that I can't legitimately recognize that as the cause of my own belief and let the unbeliever know what I believe about the Holy Spirit.


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## Brian Withnell (Feb 25, 2009)

Confessor said:


> Brian Withnell said:
> 
> 
> > That the universe is logical (as an inherent trait) does not seem to (at first blush) mean that it must have additional axioms which are universal and prescriptive.
> ...



Boy are we going to get an  on this one. 

The axiom (postulate in geometry) that is different is the parallel postulate. In Euclidean space, it states:



> Given a line and a point not on the line, there is exactly one line through the given point parallel to the given line.



It is directly contradicted by the spherical postulate which states there can be no parallel lines. (The technical language for it I have not looked up in a while, so I'm not willing to put it into a quote box.) Spherical geometry is geometry on a sphere (one model) in which lines are "great circles" of the sphere. Every great circle on a sphere intersects every other great circle at two points ... and is the shortest distance between those two points (which is why it is used in aviation).

If you used Euclidean geometry to plot courses for airplanes and used the shortest distance, you would crash the airplane into the ground trying to use the shortest distance between two point (a line).

I think I see your point on the laws of logic, but there are precious few laws for logic: identity, non-contradiction, excluded middle, commutativity, associativity and the distributive law; and those laws of logic are rather bare in what they state.

What I see though (dimly, I'm not the mathematician I once was) is that logic is ruled by convention. I've taken a course on mathematical modeling and in it, an entire section was devoted to Boolean Algebras (note the plural) and logic in general. The laws I stated above are those of a Boolean Algebra. That does not mean there are not other logic systems (I know there are) in which some of these "laws" are non-existent. It doesn't mean the systems are not logical, but that they operate differently than what we are used to operating. For that matter, most people operate on an emotional level not a logical level.

-----Added 2/25/2009 at 11:23:34 EST-----



armourbearer said:


> Confessor said:
> 
> 
> > This is the thinking that denies presuppositionalism in the first place. "You can't do that; you must prove it by some other means." No, I simply do _not_ have to appeal to a higher authority to validate any work of God. You may ask how I know it is a work of God, but the answer is that I simply _know_ it. If I had to make it accord with a higher authority, then God would not retain any authority. His witness is infallible, and I don't have to "prove" its infallibility; that is an absurd concept.
> ...



The only fruit that the Bible states must be shown is that it conforms to the Bible. So the Bible is its own confirmation. WCF:



> 4. The authority of the Holy Scripture, for which it ought to be believed, and obeyed, dependeth not upon the testimony of any man, or church; but wholly upon God (who is truth itself) the author thereof: and therefore it is to be received, because it is the Word of God.
> 
> 5. We may be moved and induced by the testimony of the church to an high and reverent esteem of the Holy Scripture. And the heavenliness of the matter, the efficacy of the doctrine, the majesty of the style, the consent of all the parts, the scope of the whole (which is, to give all glory to God), the full discovery it makes of the only way of man's salvation, the many other incomparable excellencies, and the entire perfection thereof, are arguments whereby it doth abundantly evidence itself to be the Word of God: yet notwithstanding, our full persuasion and assurance of the infallible truth and divine authority thereof, is from the inward work of the Holy Spirit bearing witness by and with the Word in our hearts.



There is no outward proof that confirms the Word of God to us -- if there were, we just unseated God and put the thing which confirms the word into the place of God (judging the Word by an external standard). The Bible is Canon; it is the standard by which all else is judged.

While I might look at the arguments of someone that does not accept the Bible as canon, I do not believe their axioms are those upon which the universe is founded. Seeing the system allows me to push it to the limit that the person does not believe (most people do not hold that the universe is meaningless regardless of where they start).


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## Confessor (Feb 25, 2009)

Brian Withnell said:


> > Given a line and a point not on the line, there is exactly one line through the given point parallel to the given line.
> 
> 
> 
> It is directly contradicted by the spherical postulate which states there can be no parallel lines. (The technical language for it I have not looked up in a while, so I'm not willing to put it into a quote box.) Spherical geometry is geometry on a sphere (one model) in which lines are "great circles" of the sphere. Every great circle on a sphere intersects every other great circle at two points ... and is the shortest distance between those two points (which is why it is used in aviation).



Doesn't the fact that spherical lines are on _spheres_ make a huge difference? In that case, the propositions would not correspond, because they're not referring to parallel lines in the same _sense_, and logical contradictions have to include propositions that are identical in that regard. For instance, f I said I have a cat "A" but I do not have a cat "B," I would not be referring to the same cat and therefore there would be no contradiction in stating the possession of one and the lack of possession of the other. Likewise, if I say that all non-spherical lines have exactly one parallel line, yet all spherical lines have exactly zero, then I am not referring to the same subject and therefore there is no contradiction.

Or perhaps I still know too little about geometric axioms.



Brian Withnell said:


> I think I see your point on the laws of logic, but there are precious few laws for logic: identity, non-contradiction, excluded middle, commutativity, associativity and the distributive law; and those laws of logic are rather bare in what they state.



I think "concise" might be a better word than "bare," seeing as the laws, though small, are the ground of all thought.



Brian Withnell said:


> What I see though (dimly, I'm not the mathematician I once was) is that logic is ruled by convention. I've taken a course on mathematical modeling and in it, an entire section was devoted to Boolean Algebras (note the plural) and logic in general. The laws I stated above are those of a Boolean Algebra. That does not mean there are not other logic systems (I know there are) in which some of these "laws" are non-existent. It doesn't mean the systems are not logical, but that they operate differently than what we are used to operating. For that matter, most people operate on an emotional level not a logical level.



I've never heard of different systems of logic abandoning any of the aforementioned foundational laws. Maybe I'll have something to learn in my _logic_ class next quarter. 

Regarding people who usually think emotionally, it doesn't follow that they still don't use logic or that they do not have to provide an account for it.

Lastly, thanks for posting the WCF quotation.


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## MW (Feb 26, 2009)

Brian Withnell said:


> The only fruit that the Bible states must be shown is that it conforms to the Bible. So the Bible is its own confirmation.



This is a contradiction. That which conforms to the Bible is not in the Bible. There must a particularisation which applies the biblical principle to the real world. This particularisation -- like works in relation to justification -- is a fruit and evidence that the principle which produces it is true.


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## Brian Withnell (Feb 26, 2009)

armourbearer said:


> Brian Withnell said:
> 
> 
> > The only fruit that the Bible states must be shown is that it conforms to the Bible. So the Bible is its own confirmation.
> ...



Contradiction is that something is both A and not A at the same time in the same relationship.

The Bible completely and perfectly conforms to itself and has to (nothing can be different from what it is, so anything will conform to itself).



> We are from God; he who knows God listens to us; he who is not from God does not listen to us. By this we know the spirit of truth and the spirit of error.



John says that those that listen to "us", the writers of the scriptures, is from God, and those that do not are not from God. The test of Godliness is the scriptures.

This is no different than what Paul says in Romans 9:


> You will say to me then, “Why does He still find fault? For who resists His will?” On the contrary, who are you, O man, who answers back to God? The thing molded will not say to the molder, “Why did you make me like this,” will it?



In this, Paul says that man cannot complain about God choosing, God is God and the authority begins with him. His word needs no evidence or proof; his word is the axiom upon which everything else is built and is the standard by which all else is measured.

I'm wondering if we are talking past each other here.

What I'm saying is the Bible is the standard by which any fruit would have to be judged ... it is beyond proof (or even showing of evidence like works in justification) because it is what measures all else.

Back when a meter was the length between two marks on a particular platinum/iridium bar (instead of how far light travels in a vacuum in a *really* small, specific amount of time) the bar was the standard. You didn't measure the bar to find out how far it was off ... it was the definition of a meter. When it was compared to anything else, the other thing was what was being measured. The same is true for the Bible. It measures everything placed against it, not the other way around.


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## DonP (Feb 26, 2009)

davidsuggs said:


> The problem with the term "self-evident" is clearly underlying the context of this discussion. "Self-evident", or even "evident" for that matter, is only concerned with the subjective perception of an individual.
> 
> Excellent point. Evolution is self evident to many and to Darwin it was self evident there was one source of all life, though I would not call him an evolutionist in today's terms, he was really only viewing natural selection with in species. Which may not even be true.
> 
> ...


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## MW (Feb 26, 2009)

Brian Withnell said:


> What I'm saying is the Bible is the standard by which any fruit would have to be judged ... it is beyond proof (or even showing of evidence like works in justification) because it is what measures all else.



This is true in itself, and this is what is meant by calling the self-authenticating revelation of God in the Bible the starting point for the Christian. But what are you going to do when somebody asks you where the Bible can be found? Your idealism isn't going to work so well in the real world when you are forced to particularise your starting point. Somewhere or another you will have to give an account of your "Bible," and when you do it won't be the Bible which proves itself to be the "Bible."


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