I may be skipping a step or two in my explanation of why I am a Catholic, but this post is going to be about why I believe in the Resurrection of Jesus, from a purely intellectual standpoint.
For me, one of the most interesting pieces of evidence for the Resurrection is in the Gospel of Matthew, chapter 28, verses 11-15. I like this passage because it does not require any real leap of faith from the reader on any level: you don't have to believe that it was written by Matthew, you don't have to believe that it was inspired by God, you don't have to believe that it's inerrant, you don't even have to believe that it gets the historical details of Jesus' life right, because the most relevant part isn't about the historical details of Jesus' life. The only thing you have to accept is that this is a piece of writing that dates from some time in the 1st century.
The passage comes right after an angel has announced Jesus' Resurrection to Mary Magdalene and "the other Mary" (I love that) at the empty tomb and Jesus has appeared to the two women and told them to go to Galilee and tell His brethren the news. It reads:
"While they were going, behold, some of the guard went into the city and told the chief priests all that had taken place. And when they had assembled with the elders and taken counsel, they gave a sum of money to the soldiers and said, 'Tell people, "His disciples came by night and stole him away while we were asleep." And if this comes to the governor's ears, we will satisfy him and keep you out of trouble.' So they took the money and did as they were directed; and this story has been spread among the Jews to this day."
Now, the part I find so interesting is that last little bit: "and this story has been spread among the Jews to this day." Up to the time this passage was written, decades after Jesus had died, the story was still going around that Jesus' disciples had stolen His dead body from His tomb, the author claims. Now, I've been told I'm a fairly cynical guy, but I can't think of a good reason why the author would include this detail unless it were true. Biblical scholars all agree that the author of Matthew was a Jewish Christian writing for a community of Jewish Christians -- why would he sabotage his credibility by lying about an ongoing phenomenon that any of his readers could not help but verify?
So if we accept that the author of Matthew wasn't a raging liar (at least about current events), what this passage tells us is that even those who opposed Christianity and who certainly didn't believe in the Resurrection were still trying to explain an empty tomb! That Jesus was no longer in His tomb the Sunday morning after His Crucifixion was not disputed, even by those who sought to discredit Christianity. It was acknowledged as a fact and then explained away.
If even early opponents of Christianity argued from the premise that Jesus' body went missing from His tomb, it seems logical to me to believe that His body really did go missing from His tomb. The question we then have to ask is, why was it missing? Which story are we going to believe? Did Jesus' disciples steal His body in the night while the guards were sleeping? Or could it be possible that Jesus actually rose from the dead, that He truly was God?
To be honest, it's much more difficult for me intellectually to believe that Christianity was founded on a hoax that began with the disciples stealing Jesus' body from His tomb. Setting aside the question of whether the often clueless disciples could have pulled off such a feat, what could their motivation for perpetrating such a hoax possibly have been? If Jesus hadn't risen from the dead, if He really wasn't God, why would His disciples have started a religion that claimed that Jesus did rise from the dead and that He was God?
Because they just couldn't let go, or admit they were wrong to hope that Jesus was the Messiah? On the contrary, nearly all Jesus' disciples had already abandoned Him before He was crucified. Peter denied three times that he even knew Jesus when the going got tough.
Because they wanted the great power that comes with founding a new religion? None of Jesus' disciples lived nearly long enough to see the Church grow beyond being a handful of tiny communities of believers.
Maybe because they were all a bunch of weirdo masochists. Maybe Jesus' disciples wanted to spend the rest of their lives toiling and suffering for no earthly gain. Maybe they thought it would be fun to be cast out of their communities. Maybe they liked being persecuted, jailed, and beaten. Maybe they'd always thought it would be neat to be murdered. And all for a hoax.
No, that doesn't make sense at all. The tomb was empty on Easter morning, and the only reasonable way to make sense of the disciples' post-Easter lives, in which they so willingly submitted themselves to great suffering, is to believe their story: that Jesus truly rose from the dead and that He truly is God and the Savior of the world. That is a truth worth dying for.