One of the reasons this idea has come to be what I would say is the biggest problem to ever come to light is because of writings from men like Immanuel Kant, Voltaire, Soren Kierkegaard and Benjamin Franklin (that's right, a founder of our country pushed along what could be the biggest problem Christians will ever face in evangelism or religion at all). Let's look at some quotes from these men:
"The Truths of religion are never so well understood as by those who have lost the power of reason." - Voltaire
"The idea of demonstrating that [God] exists, could scarcely suggest itself to reason." - Kierkegaard
"The way to see by faith is to shut the eye of reason." - Franklin
Do we see a connection in these statements by these very intelligent, but very mislead men? Yes, the idea that religion and reason are to be separated. Where did that thought come from? The man Immanuel Kant who forever changed the face of religion on the earth during the 18th century.
But, what these men didn't realize is that the religion given by the Creator of the Universe, i.e. Christianity, is not separate from the reason which He placed into us at the beginning! God created man in His image, that is to say with aspects of His own personality. I believe very strongly that reason is one of those aspects! God gave us the ability to look at the evidence, decide whether or not we were going to follow Him, and act on that decision. That is why we have passages in the Bible like, "Come now, let us reason together saith the Lord (Isa. 1:18)," "He that believeth and is baptized shall be saved (forever linking the personal belief founded on evidence with obedience to that belief)" and many more. Thomas Aquinas, philosopher and theologian, put it wonderfully when he wrote, "To disparage the dictate of reason is equivalent to contemning the command of God."
How do we please the God of the universe?
- We look at His creation, thereby seeing the majesty and power of the Creator. Psa. 14:1
- We reason in our own selves that this God is not some made up thing by men long ago, but a living and active God who has given us divine instruction on how to live our lives and be pleasing to Him (i.e. the Bible) (2 Tim. 3:16-17, 2 Pet. 1:3).
- Obey everything the Lord has given us to do so that we can please Him and He will accept us (Mat. 7:21ff).
Our God isn't something that is irrational and petty, but is something that is rational to the utmost degree and the only thing by which we should live our lives (Ecc. 12:13, John 12:48).