I would find them under the category of patterns.

A neural network is very good at recognising patterns; and human brains run on a neural network architecture. Given a few examples of what a word does or does not mean, we can quickly recognise the pattern and fit it into our vocabulary. (Apparently, this can be used in language classes; the teacher will point to a variety of objects, indicating whether they are or are not vrugte, for example; and it won't take that many examples before the student understands that vrugte means fruit but not vegetables).

Justice and mercy are not patterns of objects, but rather patterns of action. The man killed his enemy, but has a wife and children to support; sending him to Death Row might be just, but letting him have some way of earning money while imprisoned might be merciful. Similarly, happy, sad, and angry are emotional patterns; a person acts in this way when happy, and acts in that way when sad.