Then some of the Pharisees and teachers of the law said to him, "Teacher, we want to see a miraculous sign from you."
He answered, "A wicked and adulterous generation asks for a miraculous sign! But none will be given it except the sign of the prophet Jonah. For as Jonah was three days and three nights in the belly of a huge fish, so the Son of Man will be three days and three nights in the heart of the earth. The men of Nineveh will stand up at the judgment with this generation and condemn it; for they repented at the preaching of Jonah, and now one greater than Jonah is here. The Queen of the South will rise at the judgment with this generation and condemn it; for she came from the ends of the earth to listen to Solomon's wisdom, and now one greater than Solomon is here.
In today's gospel people ask Jesus for a sign. They don't really want one. Jesus essentially says No. I won't give you a sign. I won't force you to believe. Arguments are a lot like signs. They force you to believe something whether you want to or not. But arguments for the faith are not that airtight.There is always a way out if you really want one. Arguments for the church are similar. People who come asking for an airtight argument don't want one. God will not force one on them.
Dave Armstrong has a book called 150 Reasons I'm Catholic. Devin Rose is working on one called 50 Roads to Rome. They both sound like good books. They both try and look at the Catholic faith from many different angles and show how the amazing truth of Catholic church is evident by a wide variety or arguments. But none is airtight on it's own. The one, holy, catholic, and apostolic church is a matter of faith. That is why it is in the creed. That means you will never get a simple, inescapable proof of that truth. Once you have that it ceases to be a matter of faith.
As a protestant I played that game for a while. I looked for escape routes and always found them. But there was a point at which I asked myself why I kept looking for ways out. Why not look for a way in? Over and over again I would reject a Catholic argument but be amazed by it at the same time. The idea that "if that were true it would be so awesome but it is not true". In fact, I remember the "too good to be true" objection launched against Christianity. If people thought protestant Christianity was too good to be true this was so much better.
Anyway, we need to keep asking when we look for signs or arguments if we really want them? Are we really willing to humble ourselves and obey? Sometime God makes us wait and suffer and demand a grace before He gives it. He wants us to want it bad before we try and proceed down that road.