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. Empiricists never consider this philosophical fact about science.
Ideas present the universal.
Please note in passing that modern philosophies are deeply imbued with nominalism, a bald claim that to use terms like universal and abstract is to speak of what has no relation in reality. They also dislike terms like potential and act. Indeed if there were no other reason for the development of modern positivist philosophies this denial of things essential to intellectual freedom would be enough.