I said that I think that the common nouns (or general and mass terms) are referring to multiplicity as intentional content. That is, as proper names are given to something that appears as intentional content (be it that we become aware of it through seeing, touching, etc…, or we heard about it from someone else, or assume it, imagine it, etc..), those common nouns are given to some multiplicity (again, it might be assumed, imagined, and so on). If a person sees one rabbit, then another rabbit which reminds him of the first, and then another and another, he becomes aware that there is some kind of multiplicity in the world. And he can give name “rabbits” to this multiplicity.
There are few thoughts I want to add…
A person doesn’t just come out from some unconscious state, become aware there is some multiplicity, just to get back to unconscious state again. A person encounters this multiplicity usually in the context of which he is aware. For example, a person is aware that he has drove from the city to the nearby woods, and that is where he saw the rabbits. So, he becomes aware of this multiplicity, but this is not without context.
a) The salience has important role what one becomes aware of. Salience means that some things will tend to attract attention, and you will most probably become aware of them with or without trying. Some other will require more deliberate attention to become aware of. A jumping rabbit is salient. Its parts aren’t so much. Things are probably in general more salient then their properties. So, usually we will become aware of some things, and not of others. (Just to avoid misunderstanding – I don’t mean that salience is property of the things)
Similarities can be more or less salient too. Gestalt similarities seem more salient in general than similarities that require putting attention to parts (I guess, this is understandable?). Gestalt similarities are where you don’t need to become aware of the characteristics of the things. Faces are similar even you haven’t put attention to any characteristic of those faces. The second rabbit reminds you to the first one, and you leap to thinking of “these things” even you might not really know even how many legs those have, if they have fur or not, and so on. First rabbit was salient, the second one was salient too, their similarity was salient, enough to think of them as multiplicity. (One can point to researches like of Vygotsky where children were given blocks of different color, form and size, and was asked to categorize them. Younger children didn’t categorize them on base of any of those properties.) Of course it is no rule, gestalt similarity might be less salient then some characteristic property. Even kids would probably categorize humans with fully dark eyes (like in the horror movies) on one side and all other “normal” people on another.
Even in the gestalt similarities, there are more and less salient ones. Gestalt similarity among trees (which makes one think – “ah, another of those things”, and name them “trees”) is more salient than gestalt similarity between sequoias. We will most likely become aware of trees, before we become aware of sequoias.
b) The salience of things and similarity is changed through the life, we become aware of different things that were not so salient… those things might be interesting for us, because of this and that, probably we train ourselves to recognize faster those things, and as result their salience grows. Some other things… they become uninteresting and get pushed in the background (one rabbit or two rabbits will be salient, but if for few hours they keep appearing every minute, we probably won’t notice them any more after that).
Even some basic categorization can be based on this kind of salient similarities, one can become aware of some less salient properties, on base of which one can categorize things (for this or that use). We become aware of the common properties of animals, we become aware of social relations, we become aware of chemical properties of elements.
Even the salience of a similarity or a thing is not something which belongs to the object as such, but it is connected (by definition) to how much this object attracts our attention, or how much we tend to notice that similarity; still the things (which were seen as similar) are real, and hence when they are named the name connects to the awareness of those real things which are similar in some way. For example – the word “rabbits”. That “rabbits” refer to a multiplicity, doesn’t mean that there won’t be cases for which we won’t know if they are rabbits or not. There is no Platonic form of rabbit, which any rabbit will satisfy, nor I think it is some concept in our head that defines what we consider a rabbit. . “A rabbit” is just one of this specific multiplicity that we became aware of.