Philosophy claims to be neutral and to be conducted on a purely rational basis. Yet, as we look through the vast diversity of philosophical systems and insights, we are forced to account for this diversity through appeal to more than rational factors. Philosophical concepts themselves require that we dig deeper.
In modern philosophy there is the basic motivation of personality/freedom and science/control which needs to be understood if we are to grasp the way concepts and arguments function. These two are in constant tension. Through science, humans come to understand the world. This delivers us from the fear of the mystery of nature. Further, our scientific knowledge gives us power over nature. This power means that we can free ourselves from the capricious power of nature; we can even use the power of nature for our own benefit. So science creates huge potential for human freedom. Seen from a humanistic view point this freedom is created by humans. It is our power of reason that creates it, and through reason this freedom can become total. Nature is an object that we can know completely and over which we can have complete power. We can become gods.
How do we gain complete control over nature? We do this through strict adherence to the power of reason to analyse everything and to see the interconnections of everything. This includes humans and human society if we are to have complete control over them. It is not too hard to see that, along this path, what appeared to guarantee and to be irrefutable evidence for human freedom turns out to destroy human freedom, either through a deterministic science or social engineering. This kind of problem has gone through many permutation over the last four centuries, the point to note is that underneath it we have a basic religious conviction of a humanistic kind.
Despite the fact that the history of philosophy requires us to take pre-rational factors seriously, it can still be held that neutrality is an ideal not yet attained. A second line of argument seeks to show that philosophy is not possible without a religious starting point; there is an inner point of contact between religious belief and theory. This point of contact is to be found in certain basic ideas that make philosophy possible. They are the ideas of (1) origin, (2) unity, and (3) diversity in coherence.