If abductively necessary, then reasonable
In this thread, I want to establish that IF Christianity is an abductive necessity, THEN Christianity is reasonable. I want to get this premise through by itself before I go show exactly why it is abductively necessary. I have seen that I really have to take it One. Step. At. A. Time. with you people.
I want to begin by establishing what I mean by limited. By that, A cognitive faculty is limited if it is such that it may apply every test within its power to some proposition "x" and come to believe "x", while "not x" is the case. In other words, it is possible for some idea to be 100% reasonable, yet false. Here's an example: A very very young child might see a straw inserted into a glass of water, note that the straw appears to bend, and conclude that straws bend when inserted into water. Within the young child's context of knowledge, this is reasonable, and even the most strenuous logical analyses could not change that. But it's false!
That's what I take "limited" to mean. Now we're going to see how limited we are, i.e., in what specific realms the human faculty of cognition is limited. There are two sorts of propositions: empirical and a priori. Empirical propositions, i.e. propositions that take their persuasive power from sensory data, are all potentially flawed. Your eyes, your ears, your hands; all of these are bits of matter sending you bits of electricity. They can misfire. A source of information that may misfire cannot provide you with certainty. So you are limited to the realm of the a priori, right? But wait! A priori propositions are no surer. Your mind can lapse just like your senses. If you have ever made a mistake on a math problem, you have come to a false a priori conclusion. So the mind, just like your senses, may be wrong. And a source of information that may be wrong cannot provide you with certainty. Since all propositions are either empirical or a priori, and you are limited both in the a priori and empirical realms, you are totally limited. All of your beliefs, from "A is A" to "Obama's economic policy rules" are produced by a limited faculty of cognition.
Since the human faculty of cognition is totally limited, it must employ the following two concepts to survive in reality: (1) induction and (2) abductive necessity. Induction permits us to move from past statesof affairs to future states of affairs via inductive propositions, and abductive necessity permits us to unify inductive propositions into abductive propositions, or explanations. When we discovered that water boiled at a certain temperature, it was an inductive discovery, since it was based upon repeated, direct observations of the boiling of the water. When we discovered that atoms have positively charged nuclei, it was an abductive necessity, since we did not directly observe the nucleus but had to declare its existence to explain why Rutherford's electrons were riocheting off the gold foil at such odd angles -- nothing else made sense of all the data. (I'm going to assume you all know the gold foil experiment.) Neither of these are really philosophically satisfying methods of gathering information about the world. A proposition that is inductively reasonable or abductively necessary may be false. They are simply how we as beings of limited means gather information about the world.
(Side note: Somebody is going to link to todangst's induction paper at this point. Before you do that, think for a second: at the end of the day, behind the equations and the rhetoric and the terminology, Did he show that the next swan must be white? No. So the problem of induction remains a problem. Don't waste my time.)
Saying that a proposition is abductively necessary means, roughly, that it's the best explanation we've got. It unifies all the data. If the Christian religion is an abductive necessity, the Christian religion is reasonable, since that is all that is necessary to establish a proposition for a limited intelligence.
Q: Why didn't you address (post x) that I made in response to you nine minutes ago???
A: Because I have (a) a job, (b) familial obligations, (c) social obligations, and (d) probably a lot of other atheists responded to the same post you did, since I am practically the token Christian on this site now. Be patient, please.