Also called the Argument from Divine Hiddenness, this is one of the most frequent arguments against God, though I've never heard it as a syllogism. Most often, I hear, “If there is a God, why doesn't He just show himself to us?” According to this argument, a personal, perfectly loving God would want all of His children to know that he exists, so the fact that people have reasonable reasons to disbelieve means there can't be a personal, perfectly loving God. This argument is similar to the problem of evil because it claims the idea of God is inconsistent with what we observe in the world. In fact, since ignorance of God would seem to be a natural evil, many say that the problem of divine hiddenness is an instance of the problem of evil.
As a syllogism, it looks like this:
1. If there is a God, he is perfectly loving.
2. If a perfectly loving God exists, reasonable non-belief does not occur.
3. Reasonable non-belief occurs.
4. No perfectly loving God exists (from 2 and 3).
5. Hence, there is no God (from 1 and 4).
If a perfectly loving God exists...
Not many theists would argue against the first premise. Many theists describe the God of the Bible as a personal God of unconditional love. In addition, no objective person would deny the existence of reasonable non-belief. Theists may not agree with atheists, but one must admit that some of their arguments are, at least, well thought out.
However, there is a good amount of controversy over the second premise; If a perfectly loving God exists, reasonable non-belief does not occur. This is allegedly because a perfectly loving God would want everyone to know he exists, in order to be saved, and would also have the power to bring about a situation in which everyone knew he existed.
Schellenberg, a major proponent of this argument, says, “The perfectly loving parent, for example, from the time the child can first respond to her at all until death separates them, will, insofar as she can help it, see to it that nothing she does ever puts relationship with herself out of reach for her child.”
The Unknown Purpose Defense
Normally, I'm opposed to the idea that “there are certain things we weren't meant to know,” but this one makes a fairly decent point. Alvin Plantinga, who is also known for responding to the Problem of Evil, writes that the statement "We can see no good reason for God to do X" only implies "There is no good reason for God to do X" on the assumption that "If there were a good reason for God to do X, we would be able to see it," which he suggests is absurd. It would be like saying, “We fully understand the mind of God.” If God does exist, then that clearly is not the case.
I find this idea a little more tolerable because it does not say that we can't know why God hasn't appeared, only that we currently don't.
The Soul-Making Theodicy
This defense is employed by Michael Murray, who explains why divine hiddeness is essential to soul-making. While based on the accounts of religious individuals, it isn't hard to imagine a world where God is known, and yet believers act freely with ample opportunities for spiritual development, Murray gives a deep and careful analysis of the argument, concluding that if God's existence were revealed in such a way as to remove reasonable non-belief, then "any desire that we might have to believe or act in ways contrary to that which has been revealed would be overwhelmed." That knowledge would then affect our choices in such a way as to infringe on our free agency, because it would cause us to act in a way that we otherwise would not, for fear of divine consequences.
As I mentioned before, many people ask, “If He does exist, why not just show himself to us?” I think the biggest reason is because it probably wouldn't help at all. After all, Cain walked and spoke with God, but that experience did not produce the faith necessary for salvation. Also, many of the Pharisees at the time of Christ saw God himself walking the streets working miracles, but they rationalized what they saw and chose not to accept it.
Of course, personal manifestations have been instrumental in the conversion of some pretty significant figures in Christian history. Paul, the Apostle, for example, brutally persecuted the early church members until Christ appeared to him on the road to Damascus. However, accounts where such manifestations lead to successful spiritual conversion, versus accounts where it had no effect, or ultimately damned the individual who was then held accountable for that knowledge, are rare enough to show that even if God Himself appeared to the world, a significant portion of the world's population, including many Christians, would remain unconvinced. In other words, even if God did want to make us know for sure that He exists, this would not be an effective method to do it.
If the God of the Bible actually exists, and He made himself absolutely known to the entire world, then the entire world would then be held accountable for that knowledge. The idea that we are only accountable for knowledge we possess is shown in Jesus' saying to the Pharisees, in John 9:41, “... If ye were blind, ye should have no sin: but now ye say, We see; therefore your sin remaineth.”
If the Biblical account is true, then the Christian God is a reality. The ineffectivity of a personal appearance is then an indication that some people are prepared to accept this reality, and some, for whatever reason, are not. Those who are not able to accept this truth would then be subject to judgements that would not be just, or which could have been avoided if they had been allowed more time to prepare.
The Lord, then, would need to use a more selective method of conversion than to expose everyone to this knowledge, since it could ultimately damn them. He would need a method which would only reveal Him to those who were ready to live a lifestyle that would turn that knowledge into a blessing, rather than a curse.
The Lord did propose a more effective method just before He ascended to Heaven. In Matt. 28:19, Jesus says, “Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end of the world. Amen.”
All over the world, many Christian denominations send out individuals for the specific purpose of fulfilling the Lord's command to teach all nations. The Prophet Joseph Smith once declared that all things “which pertain to our religion are only appendages” to the Atonement of Jesus Christ. In like manner and for the same reasons, every truth that a missionary or member teaches is only an appendage to the central message of all time—that Jesus is the Christ, the Only Begotten Son of God, the Holy Messiah, the Promised One, the Savior and Redeemer of the world; that He alone burst the bands of death and triumphed over the captivity of hell; that no one of us could ever have those same blessings without His intervention in our behalf; and that there never shall be any “other name given nor any other way nor means whereby salvation can come unto the children of men, [except] in and through the name of Christ, the Lord Omnipotent.”
So to those who wonder why a perfectly loving, personal God does not make Himself known to us, I say that He is, though perhaps not in the way we might expect.