A Puzzle About Concepts
When concepts enter into thoughts they occur attributively: that is, they are attributed to some designated particular or particulars. They are constituents of thoughts, and thoughts are true or false according to whether the concepts attributed hold of the things to which they are attributed. They occur in a propositional context, not in isolation. One might think that they can occur in no other way, but we also have the locution “the concept C”: here we appear to be designating the concept C not attributing it. It occurs in thought in a non-attributive manner, attached to no particular. The distinction is analogous to the distinction between the use and mention of words. Words are usually used in utterances of sentences, but we can also mention them, typically by employing quotation. We can say, “Consider the word ‘red’” as well as “The car is red”. Just as we have a use-mention distinction for words, so we have an attribution-designation distinction for concepts. That is not surprising, given the close connection between words and concepts. And it allows us to ask which came first: is the distinction for words derivative on the distinction for concepts or vice versa? If there is a language of thought, we will want to explain the distinction for concepts in terms of the distinction for internal words: attributing concepts is using words internally and designating concepts is mentioning them internally (by some analogue of quotation).
The puzzle I want to raise (but not solve) concerns the form in which concepts exist before entering our conscious thoughts. Let us allow that concepts are stored pre-consciously before they are employed in conscious thought: how then do they exist in the preconscious–in the mode of attribution or designation? Are they being used or mentioned? Neither alternative looks appealing, but nothing else suggests itself: hence the puzzle. They cannot be occurring attributively because that would imply that they (all of them) are constantly being attributed to things unconsciously. Surely we are not always thinking unconscious thoughts as a way to keep our concepts in existence. But it is also implausible to suppose that they are being mentally mentioned: we are not always taking them as objects of unconscious thought—putting them in mental quotation marks. We don’t store concepts in the preconscious in virtue of referring to them there. They exist pre-consciously but not by way of a mental act of quotation. Nor are they being constantly attributed. They are not present in either the mode of mention or the mode of use–yet they are present. Similarly, our vocabulary, stored in preconscious memory, does not exist either in the mode of use or mention: we are not constantly using the words in our vocabulary to make unconscious utterances, but neither do we store them in the form of quotation. They exist in some neutral mode, neither used nor mentioned.
Thus concepts and words do not exist in the preconscious in either of the two ways they exist in thought or speech (use and mention). This third way has no counterpart in thought and speech, but it is presupposed by thought and speech. We extract concepts and words from the preconscious and either mention them or use them, but they are not already being mentioned or used in their preconscious state. They are… And here we draw a blank: we don’t have a perspicuous description of their mode of existence—and it is hard to form a conception of what this mode might be.  We can say that concepts and words are stored in the preconscious (though what this amounts to a longstanding problem in psychology), but this doesn’t tell us anything about how they are stored. My point is that the standard notions of use and mention (attribution and designation) don’t apply. Hence there is a puzzle about concepts (and words). We have no understanding of how concepts exist in the mind.
 It is tempting to suppose that they exist as items on a list, but a list consists either of a sequence of used words or mentioned words. If I write a list of all the students in my class by inscribing their names, I am using their names to refer to them; but if I write a list of their names, I am mentioning the names (not the students). In the former case each inscription constitutes an act of reference to a student, though not in the latter case. Are we to suppose that words and concepts in their preconscious form are items on a list that refer to external things, or do they exist merely as mentioned symbols? Neither option looks attractive. (The semantics of lists could use further investigation.) And if words and concepts are stored in the form of lists, what is the principle of ordering for the list? In what sense does each item hold a place in a list?