Ancient philosophers such as Aristotle and Plato came to understand that that there was something out there greater than the human person, a First Cause, that initiated everything. Thus, they knew there was a reason for existence, yet they were not able to discern Its personal identity.
A foolish anthropocentric assumption that the First Cause would have a personal identity at all - that it would be intelligent, yet not too transcendental nor alien that human concepts of personality or identity could be applied to it.
Jesus incarnated the First Cause into salvation history. Through Christ we know the First Cause’s Name and purpose.
Or, alternatively, hellenised Jews shoehorned and mutated their traditional mythology into the Greeks’ metaphysical worldviews, eventually giving rise to syncretic cults, one of which proving to be a breakout success.
Rationalism is the natural continuation of Luther’s view of Sacred Scripture that each person can and should read and interpret the Sacred Page on his own. Yet this results in severely damaging man’s relationship to God. The relationship between God and man is no longer Father to child, but rather distant master to servant (slave). According to Rationalism, if the only communication from God is in written form (the Bible), then it is up to the reader to decide what exactly is meant.
Anti-intellectualism: When your position is so untenable that your only option is to take refuge in audicity and embrace stupidity and irrationality.