The most appropriate way of examining the relationship between philosophy and theology is from a scientific viewpoint since both are sciences. They can both be examined, just like their relationship, from a theological and philosophical perspective. It is therefore necessary that the relationship between theology and philosophy is one of mutual dialogue. Their true status can only be reached through ‘theologizing’ and ‘philosophising’. The example of a philosophical approach to the relationship between philosophy and theology is Heidegger’s examination of that very relationship. A philosopher investigates reality as a natural reality, whilst a theologian investigates it as a supernatural reality. The parallel between philosophy and theology can be seen in the fact that each has its own theory of knowledge: noetics as a theory of knowledge about the natural being, and fundamental theology or apologetics as a theory of knowledge about the supernatural being. When it comes to the relationship between faith and knowledge, there is still a predominant superficial understanding according to which the increase of knowledge and the progress of science render faith pointless and redundant. Faith, however, is not a blind and uncritical acceptance of something that is not known. Knowledge is an integral part of faith just as faith is an integral part of knowledge. This is not about confronting two basic sciences, philosophy and theology, but about seeing if they both respect the criteria of science according to which they can be merely compared. As a methodological minimum, the criteria of absence of contradiction, correct deduction, accuracy and intelligibility are suggested. Considering these, theology is no less a science than other sciences. Philosophy is not a subordinate science to theology, but is its supporting (assisting) science, whilst theology is not possible without the philosophical opinion. Therefore, they are complementary. The difference is that the unity of philosophers does not lead to some ‘philosophical faith’ whilst a theologian confirms his opinion before itself and before a community of believers.