Due to the great efforts undertaken mainly by the United Nations during the past half-century or so, there is a huge amount of positive rules in the field of human rights incorporated into the main body of International law which claim a universal observance and compliance thereto. Therefore examining philosophic foundations of such a concept might appear unnecessary and controversy-provoking. But the "sole object" of this article is to give a brief account of major old and new approaches to the issue and thereby implying that, not withstanding possible or even actual abuses on the concept, it is deeply rooted in the intellectual heritage of mankind and firmly supported by quite diverse religions and secular schools of thought. The theories dealt with include the following: religious, natural, positive, utilitarian, Marxist, policy oriented, justice, human dignity, relativism and universalism.