The TAG (transcendental argument for the existence of God) attempts to prove the existence of God (yes, that god) by postulating that logic, reason and morality can not exist with out God.

The argument is basically "where did that come from? Who decided that?". The argument fails because it assumes that the concepts of logic, reason and morality have to come from a metaphysical source rather than just be.

Logic is the study of the principles of correct reasoning and reasoning is the process of forming conclusions, judgments, or inferences from facts or premises.
Reasoning comes from out of our cognitive processes, we see the world around us and we try to make sense of it. We got the ability to reason from evolution, we evolved in a environment that selected for certain cognitive traits, specifically learning, understanding and abstract thought. Learning was selected for because our ancestors were tool using animals, understanding because our ancestors were social and tool using animals and abstract thought because (again) we were social and tool using animals. As social and tool using animals these cognitive traits gave our ancestors an advantage that made them better able to survive and ultimately dominate the environment and develop the technology we have today.
Logic came out of reasoning. Logic gave people grater ability to understand and explain things as well as come to more accurate conclusions.

But a creationist could say "logic and reason work because the universe is governed by the laws of physics and for there to be these laws there has to be a law maker".
First of all the laws of physics are not "laws" in the colloquial sense. Laws in physics are observed phenomena thats are universally true (gravity, thermodynamics). But that doesn't really deal with the question. Why the universe is the way it is? Well for one some things simply are and can't not be.
Heres some examples.

• If you have an one M&M and you add another, you have two M&M's, you do not have three or four, you have two. Even if another M&M magically appeared when you placed two M&M's together, one plus one still equals two your just magically adding another plus one to it.
• An immovable object is an object that no matter how much force you apply to it, it will not move. An irresistible force is a force that can not be resisted no matter how much it is fought. (Don't say "duh") the two can not exist in the same universe. If one exists the other can not or nether can. An irresistible force can not meet an immovable object.

These are always true, no deity decided they are true. Even a deity would have to obey these no matter how powerful it is. As for the rest of the properties of the universe (the fundamental interactions, etc) we don't know. We don't have all the information. But that in no way shape or form means some deity did it.
As for morality: I've already dealt with that.
© 2009 all rights reserved

Links
What is logic?
Dictionary.com-reasoning

<-Part 6 | Part 8->