Many years ago, a friend of mine in yeshivah made an observation. He claimed that whenever somebody gives two reasons for something, the second reason is always the real driving reason, and the first reason is secondary, but placed in the first position in order to make it more palatable and sound better. Over the years, I have seen this confirmed endlessly, in a variety of ways.
Here's a mundane example. "How are you? I called for two reasons. Number one, I wanted to see how you are doing. Number two, I was wondering if you could do me a favor..."
And here's an example that relates to the topic of rationalism. Why do/don't we believe in the Theory of Evolution? Over at Toriah.org, they give a list of reasons for not believing in evolution. The first six are scientific, and the last four are religious. It's interesting that they put the scientific reasons first!