After all, unless I am gravely mistaken, deontologists believe we should make decisions based on if a certain action is right or wrong, but not if the consequence of the action is right or wrong.

Act only according to that maxim by which you can at the same time will that it become a universal law. - Kant

From what I understand, Kant's moral philosophy is derived from his metaphysical philosophy. I have just begun trying to understand Kant's metaphysical philosophy, so I have not had the chance to see how. Perhaps another could expound on this.

Either way, I feel that deontologists have the advantage of looking beyond the surface of actions. What is right in an action comes from the universality that is the human condition. If an act can be universal good for mankind, then it is the right action to perform, not when it has the most benefit, but all the time. Why should right and wrong be determined per situation? Should whimsical humans be trusted with this responsibility?

Deontologists say you should judge the action, not the consequence of the action.

You need a rational basis for everything. Consequentialists have one but deontologists don't. You can't just judge an action without judging its results.

Well, no theistic belief can be rational by definition. You're simply accepting something as fact without evidence.

First of all, it still focuses on the consequences of actions in a way, so in itself, it is somewhat consequentialist.

Secondly, it deems actions immoral by effectively saying, "well, if everyone else did it, then..."

This reasoning doesn't fit every single situation. Take this as an example:

A criminal took you and your family hostage. You know for a fact that he will kill you and your family. You either have to kill him or let your family and yourself die.

I don't see how a case can be made for the categorical imperative being rational when it causes such huge contradictions.

That's not what the Scholastics thought, or predecessors to them like Maimonides. People believed for centuries that prophets were equivalent to philosophers, and therefore it was rational to build logical systems on prophecy. People did rational God proofs that are logically unassailable (which still doesn't prove existence -- it only proves logical coherence).

That's not what it says... it says that when presented with a situation, you should act in a way that you think would be a universal rule for everyone. In other words, if you're about to steal a loaf of bread, would you universilize this action such that everyone must steal that loaf of bread if given the opportunity?

Well I need to do some more reading on deontology for sure, so I'll be picking up some of Kant's work later, when I have more time.

If we're going to debate the existence of God, maybe we should do it in the philosophy of religion or forum, or better yet, in the debate forum!

My point in that was that there is no rational reason to believe in God. The beginnings of the universe, earth, mankind, etc. have already been explained in a rational manner by science. Why would one believe in an infinitely complex being existing before the simple singularity?

Furthermore, there is absolutely no rationality behind believing that one's prophets are better than the other's, or that one's texts are the only really sacred texts. Even if God was a logical concept, there is no way you could prove that one religion is the true religion, and therefore, deontology derived from such scriptures, prophets, etc., are irrational.

My meaning by "if everybody else did it, then..." was that if it was a universal law, what would it mean to the human species and the world? i.e. if everyone committed suicide, well, there wouldn't be a human species any more.

One sees at once that a contradiction in a system of nature whose law would destroy life by means of the very same feeling that acts so as to stimulate the furtherance of life, and hence there could be no existence as a system of nature. Therefore, such a maxim cannot possibly hold as a universal law of nature and is, consequently, wholly opposed to the supreme principle of all duty.