An argument against naturalism

[DeistPaladin]

C.S. Lewis loved working backward from the presupposition and made a number of "arguments" based upon it. The most famous is his "trilemma" (Liar, Lunatic or Lord). Another, featuring prominently in Mere Christianity, is his argument from morality. Other famous "arguments", like the Ontological, follow his pattern.

Could someone help me out here? Starting with a preconceived idea and looking for evidence to then support it is a formal logical fallacy. We see this in a lot of creationist arguments as well. Which one is it? A Priori?

Constructing such arguments typically involves any of the following:

- Presupposition determined prior to the construction of the argument
- Unwarrented assumptions
- False dilemmas or trilemmas
- Strawmanning of undesireable conclusions.
- Oversimplification or sweeping generalizations

Now we can break down each of these arguments (Ontological, the moral lawgiver argument, the Trilemma, etc) but they all boil down to Lewis wanting something to be true so he searches for any excuse to believe it, no matter how many logical fallacies are committed. The presupposition is always the core fallacy, much like a spoke to a wheel.

Now on to the argument against naturalism:

1) For an assertion to be capable of truth or falsehood it must come from a rational source.
2) No merely physical material or combination of merely physical materials constitute a rational source. (i.e. anti-panpsychism)
3) Therefore, no assertion that is true or false can come from a merely physical source.
4) The assertions of human minds are capable of truth or falsehood
Conclusion: Therefore, human minds are not a merely physical source (see explanation below).

Point 1. Blur the lines between truth and falsehood with factual and not factual. The "truth" is that you can say something that's wrong and not be lying if you really believe it. A calculator, if damaged, might give you wrong numbers but that doesn't mean it has a soul.

Point 2. "Panpsychism" or the believe that the universe as a whole is conscious, is confused with materialism. This is a strawman argument. The alternative undesirable conclusion is being misrepresented at this point.

Point 3. Non psychic sources, whether mechanical or biological, can give false information. A damaged computer might give a false conclusion. A damaged ear might hear ringing that isn't in the external environment.

And the argument for God:

(5) A being requires a rational process to assess the truth or falsehood of a claim (hereinafter, to be convinced by argument).
(6) Therefore, if humans are able to be convinced by argument, their reasoning processes must have a rational source.
(7) Therefore, considering element two above, if humans are able to be convinced by argument, their reasoning processes must have a non-physical (as well as rational) source.
(8) Rationality cannot arise out of non-rationality. That is, no arrangement of non-rational materials creates a rational thing.
(9) No being that begins to exist can be rational except through reliance, ultimately, on a rational being that did not begin to exist. That is, rationality does not arise spontaneously from out of nothing but only from another rationality.
(10) All humans began to exist at some point in time.
(11) Therefore, if humans are able to be convinced by argument, there must be a necessary and rational being on which their rationality ultimately relies.
Conclusion: This being we call God.

Points 5 and 6: Confuse "convinced by argument" with "argument is true". People are convinced all the time of crazy things for emotional reasons.

Point 8: Unfounded assumption to support the conclusion. People can turn out to be right following faulty logic just by good fortune.

Point 9: Unfounded assumption that I shouldn't have to explain to this crowd.

Nearly every one of C.S. Lewis' arguments consist of this pattern of working backward from the desired conclusion. The "Trilemma" and his argument from morality follow this pattern.