THE CONSTITUTION OF THINGS NATURE may be material and concrete on the one hand and ideal and abstract on the other one. The nature of the water is H2O, the nature of the light are electromagnetic waves, the nature of a television are electronic circuits accompanied by a screen. They are some examples of material nature. The nature of numbers is to express a certain amount, the nature of goodness is to do good, the nature of justice is to give everyone what they deserve. They are examples of ideal nature. All values are ideal nature. Time is a DUALITY, has two natures: the becoming and a mnemonic illusion. As the becoming is very elusive, in our minds only remains a mnemonic ilusion of it. Despite these latest ideas, B-T duality (becoming-time) remains the conceptual representation of TIME. B-T Duality is a theory of time.