Recently, I visited 21st Century Christian Philosopher who has written an interesting piece rebutting part of Michael Martin's Transcendental Argument for the Existence of God entitled Contingent Necessity.
The portion of Martin's argument that 21st Century Christian Philosopher rebuts is Martin's argument against the existence of God based on Logic. Here is Martin's argument:
Some Christian philosophers have made the incredible argument that logic, science and morality presuppose the truth of the Christian world view because logic, science and morality depend on the truth of this world view . Advocates call this argument the Transcendental Argument for Existence of God and I will call it TAG for short. In what follows I will not attempt to refute TAG directly. Rather I will show how one can argue exactly the opposite conclusion, namely, that logic, science and morality presuppose the falsehood of the Christian world view or at least the falsehood of the interpretation of his world view presupposed by TAG. I will call this argument the Transcendental Argument for the Nonexistence of God or TANG for short.
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How might TANG proceed? Consider logic. Logic presupposes that its principles are necessarily true. However, according to the brand of Christianity assumed by TAG, God created everything, including logic; or at least everything, including logic, is dependent on God. But if something is created by or is dependent on God, it is not necessary--it is contingent on God. And if principles of logic are contingent on God, they are not logically necessary. Moreover, if principles of logic are contingent on God, God could change them. Thus, God could make the law of noncontradiction false; in other words, God could arrange matters so that a proposition and its negation were true at the same time. But this is absurd. How could God arrange matters so that New Zealand is south of China and that New Zealand is not south of it? So, one must conclude that logic is not dependent on God, and, insofar as the Christian world view assumes that logic so dependent, it is false.
Restated in syllogistic form, Martin argues:
L1. Logic presupposes that its principles are necessarily true.
L2. According to the brand of Christianity assumed by TAG, God created everything, including logic; or at least everything, including logic, is dependent on God.
L3. If something is created by or is dependent on God, it is not necessary — it is contingent on God.
L4. If principles of logic are contingent on God, they are not logically necessary.
L5. If principles of logic are contingent on God, God could arrange matters so that a proposition and its negation were true at the same time. But this is absurd. How could God arrange matters so that New Zealand is south of China and that New Zealand is not south of it?
L6. Hence logic is not dependent on God, and, insofar as the Christian world view assumes that logic so dependent, it is false.
21st Century Christian Philosopher (21-CCP) raises a couple of interesting responses to Martin's argument based on the distinction between necessary and contingent:
I also believe that Martin misconstrued the TAG argument (Transcendental Argument for God) in this case. TAG-gers argue that Logic is necessary for the orderly world. So in seeing this, God brought Logic into being for this purpose. To then argue that Logic is then contingent upon God’s design and so not necessary for what he intends, misses part of the framework.
To one sense, to view God as “perfect” means that we accept that all His steps were “necessary” to “work to the good”. To then say, that they were “contingent” upon God’s intent, and thus not necessary, likely throws an equivocation in there somewhere.
However, I can go further in examining Martin vs. the Anthropic Principle. I can say that only in a world where Logic divides a proposition from its contradiction would it be enough of a thing to remark that it acts in such a way. Because were it not to act in this way, in the local condition, we could not say that it definitely does not act the other way as well. Thus we would not see the face of Logic as non-contradictory, but as incoherent mixture.
Of course this makes no sense, but only in a world where the forces combine to make sense can we observe what makes no sense. Without that pre-condition, we’re in a world that makes no sense, and regard proposition that both make sense and do not make sense.
If Logic is in fact contingent, I wonder how it was that Martin saw Logic as necessary at all. The world just does not produce “necessary Logic”.
Overall, I like 21-CCP's response. Certainly, there may be questions about the usage of the terms necessary and contingent in the original TAG. If, as 21-CCP proposes, the proponents of the TAG argue that God created Logic because it was necessary for an orderly world, then it seems to follow that Logic could be both contingent (being something created by God and not necessarily existing) and necessary (at least from our human perspective). I also like the fact that 21-CCP looks at the argument from the perspective of what the world would be like if the laws of Logic were not in place. However, I think that Martin's argument is wrong on an even more fundamental level. Specifically, I believe L5 is wrong in that it does not follow that if Logic is dependent on God that God could "arrange matters so that a proposition and its negation were true".
First, it seems axiomatic that God did not create Logic in the sense that He decided that He should create rules of thinking that would govern the universe. If God exists and is the source of everything, Logic must be part of His being. To see why, consider what would happen if the principles of Logic were not in existence in some sense until God "created them" in some way. If that were true, then those principles of Logic would not apply to God -- including the Law of Non-contradiction -- at least until God created them. Then it would be the case that prior to the creation of Logic God could exist and not exist at the same time and in the same way. It would also be the case that God could be good and not good at the same time and in the same way. While this would certainly resolve many apologetic issues (both atheists and theists would be correct about God's existence and his goodness, or lack thereof), it would seem to be a completely intolerable situation even for God. Thus, it seems clear that some form of Logic must has existed either independent of or as part of God and that it is not something that God created at a later time.
Arguments can be made on both sides about whether Logic exists independent of God or as a part of God's character. If the former, then the principles of Logic exist independent of God and God doesn't create them. If the latter, then Logic would flow from God in the same way that Christians posit that goodness is part of God's character and flows from God. If goodness flows from God it allows God to be the source of goodness while at the same time not leaving God free to define goodness arbitrarily such that God could have arbitrarily called murder or lying good instead of evil. In other words, God is good because goodness is part of what He is. When God tells us what is good, we can be sure it is actually good and not arbitrarily created rules of goodness because goodness flows from God's character.
By the same token, if Logic is part of God's character, it doesn't exist independent of God. At the same time, because it is part of God's character, God wouldn't create the principles of Logic arbitrarily. Instead, the principles of Logic would flow forth from his person such that the Law of Non-contradiction, for example, would have to be the case and God could not make it otherwise without violating his own character.
What's important to note in either case of the source of Logic is that the principles of Logic are not arbitrary. Either they exist independent of God (meaning God didn't create them) or they exist as part and parcel of God's character. In the latter case, the principles of Logic are dependent on God, but they are not "created" as such. However, because they are part and parcel of God's character, the principles of Logic are dependent upon God and support the Transcendental Argument for the Existence of God.
Martin's argument argues that if the principles of Logic are dependent on God (which they have to be if they are part and parcel of God's character) then they are contingent. I agree, but only in part. If the principles of Logic are part of God's character, then if God's character were different the principles of Logic could have been different, too. But as my example demonstrated earlier, it is difficult to see how they could have been substantially different. It is especially hard to fathom how the Law of Non-contradiction could have been different since it effects even God's existence. So, assuming the principles of Logic flow from God's character (which is axiomatic to the argument that Martin is trying to rebut with his TANG), while I agree it's theoretically possible that the principles of Logic are contingent and could have been different in some minor ways, it appears unlikely that they could be different in any significant way.
Granting L1 through L4 for the sake of argument only, L5 fails because it assumes that God is free to make the rules of Logic whatever He desires. Recall that L5 states:
If principles of logic are contingent on God, God could arrange matters so that a proposition and its negation were true at the same time.
This seems to me to be a reasonable argument if one accepts the assumption that God could have arbitrarily made the principles of Logic whatever He liked. However, since I think serious reasons exist to doubt that God could have arbitrarily created Logic to be whatever he liked, and since an alternative explanation exists in theism (specifically Christianity) that explains how Logic could flow from God as part of His nature and therefore those principles must be dependent upon God while not being arbitrarily created by God, it seems to me that the portion of Martin's Transcendental Argument for the Non-existence of God which argues against God's existence on the basis of Logic fails.