Regarding religion, it is often assumed that by its very nature it is difficult, or for some thinkers impossible, to interpret and investigate it philosophically or scientifically. At the same time we find almost all great religious thinkers of prominent religions, have also been philosophers and many in Islam have also been scientists. They have interpreted and examined religions far more than a dogmatic or uncriticized faith, and have related their religious tenets to experiences and rational judgments. They have subjected, even divinely revealed tenets, to radical criticism. It is interesting to note that many of the philosophers, and even scientists, who have appeared in any history of knowledge at any time have also been believers in religion, and in some cases theologians. This tells that there is always a need of intellectual interpretation for religions. It also supports the fact that religion is not an abstract idealism; it is concrete and practical; that ideals are not only abstractly valid in the Platonic realm of ideas, but are realizable in the world of actual existence. Religion, just like philosophy and science, is related with the present and visible world. Its perception, in many ways, leads humanity intellectually toward the same everyday life experiences that philosophy and science investigate and address rationally.