In 1941 the mathematician Luigi Fantappiè introduced a new type of causality into the explanation of life and evolution. The equations which combine quantum mechanics and special relativity show that, in addition to causality, retrocausality is also an ingredient of our universe. Whereas causality is governed by the law of entropy (diverging tendency), retrocausality is governed by a symmetrical law which leads to the increase of differentiation, complexity and structures. Combining the two Greek words syn=converging and tropos=tendency Fantappiè coined the word syntropy in order to describe the retrocausal action of attractors, the converging tendency of evolution towards a final unifying cause which he named love.