Nowadays there is a discussion as to what is the cognitive basis of science. The issue can be approached from different directions, but one of the main issues in contention is the extent to which science has or not a distinctive cognitive structure. It will be argued for a continuity thesis. Science is not particularly different from other human activities to the extent that science arises from the integration of cognitive resources, which are common in other human activities. Science is different however in that it relies much more than other activities in modular structures of practices that have a very sophisticated normative structure which allows for a highly reliable means of comparing strategies for solving problems and comparing predictive and explanatory potentials of ideas. Such normative structures often are articulated in terms of what I call Heuristic structures.