In the Criticism of Pure Reason, the world, the human being and God are turned into speculative ideas. For contemporary cosmology, the universe is not a rational fiction : it has its own history. Matter, as the quanta physics views it, puts new philosophical questions about what the Real is. Far from being reducible to molecular biology and genetics, a living being is first of all an existent being. Human beings, endowed with the power to think, are the ultimate stage of a creative genealogy of subjectivity. Consequently, the « I » and its uniqueness is not a speculative idea. While exploring perception, neurologists have at least discovered that. Finally, even if science is still unable to claim anything about the existence of God, it should not confine itself within the limits of scientism. In the heart of philosophical reflection, the transcendence of the ultimate Real reappears. It is secret for the sensitive intuition and for conceptualisation, but remains the non-created source of the human spirit as the latter emerges in the cosmos and it is also the primus movens of intellectual and moral life.