Logic 101
A Christian is called to use their mind. Logic is one tool to use to discover Truth via the mind. Christ is the Logos: the Word (aka reason, vision, logic or order). So when we discover Truth via the mind we find order, and logic. The tools of logic are the Premise, and the Conclusion.
Logic follows several basic rules:
-The law of identity: A is A
-The law of non-contradiction: Non-A is not A
-The law of the excluded middle: Something is either A or non-A
-The law of rational inference: If A, then B
An argument is a series of propositions that follow rational inference, and result in a conclusion that is valid.
-All dogs are mammals
-This is a dog
-Therefore, this is a mammal
An argument that is invalid results from irrational inference of propositions
-All dogs are mammals
-All cats are mammals
-This is a mammal
– Therefore, this is a dog / cat
Key items to look for when someone is appealing to logic (even if they dont realize it) are signals such as: "If", or "When" or 'Because"
Such as: "If God can do all things and is all powerful, can He create a rock that even He can't move"? Or: "If God created all things, did He create sin"?
What are the logical issues with these statements? Let me know what you think!
Free Online! A classic of Christian literature, Aquinas constructed a compilation of the sum of contemporary theological teachings of his time. Includes his famous 'Five Ways' of proving God's existence.