  A second important factor, found in Islamic commentators, was the introduction of a distinction between first and second intentions, and the understanding that the first are studied in metaphysics and other sciences that deal with the extra-mental world, whereas the second are studied in logic (Pini 2003). There was considerable disagreement as to what these “intentions” are, but Aquinas conceived the first as concepts about things in the world (e.g., “cat” is a concept about cats) and the second as concepts about other concepts (e.g., “species” is a concept about such other concepts as cat and human). This new terminology led thirteenth century authors to ask what the concepts of category and of particular categories (e.g., substance or quality) are (first or second intentions?), and how the notions of first and second intentions ought to be understood.