Everything is intelligible in exact proportion to its Being . That's why we say the Being of things is the immediate object of our intellectual knowledge. Immediate means without the need for an intermediary term or an object previously known. Now we may hazard an entry into Logic proper. Well it is a classification of philosophy.
Logic is the introduction to philosophy in the strictest sense.
Logic studies reason as the tool of knowledge - the act which directs the very act of reason. To hark back, ideas are the internal likenesses of things by which the latter are represented in such a way that we can reason about them and thus acquire knowledge. Images are the internal likenesses of things by which those things are presented to us as our sensations have first made them known to us. Words directly signify ideas and at the same time evoke images. Sciences, if you will, are systems of ideas.