Greek philosophy arises as a search for the principle of all things. With Anaximander, there is a passage from a naturalistic conception to a metaphysical conception, which understands the principle as ground, that is, as an unconditional (absolute) condition of intelligibility of the finite (relative). Truth thus emerges as absolute truth because only the absolute is truly autonomous and self-sufficient, whereas the finite only arises by referring to something other than itself. The finite exists, in the sense that it stands at the level of the perceptive-sensitive experience, which configures the inevitable, but it is not, in the sense that its being is not authentic. Being coincides, therefore, with the absolute, since only by reason of its necessity (undeniability) non-being is not and never can be. In the absolute, which is one in itself, every duality disappears, so that also the identity of being and knowing emerges: knowing cannot but be and being cannot ignore being.