Is there just one science, the one we have, the given? Or on the contrary, are there several possible sciences? In the later case: which are their differences? Are they compatible? Complementary? Opposite? I will try to persuade the audience that at least three sciences can be distinguished: original blend, techno-science (normal science) and science of the postnormal age (call it transcendent science as it needs to go outside its field into the realm of decision making). I will distinguish the three at the epistemological level (arguably the deepest level) so that it may happen that what is scientific knowledge for one is not so for another.Sociedad Latinoamericana de Ecología de Vectores