Contemporary American philosophers tend to encounter the distinction between confused and distinct concepts in Descartes, and the distinction can be somewhat mystifying there—the "confused" seems a pejorative, for instance. It's interesting that the distinction is one that is already present in Aquinas. In Aquinas, the distinction is between knowing something confusedly and knowing it distinctly. There seem to be three paradigmatic ways one can know something confusedly:
- Knowing the whole without knowing the parts. For instance, we may confusedly know our bodies without knowing the kidneys.
- Knowing several individuals under a common description they all satisfy. For instance, in some sense we know all human beings—namely, we know that they are all human and hence have the properties that all humans have. But we know them under a common description here.
- Knowing a nature (e.g., humanity) under an accidental rather than essential description. Thus, if I know humanity as my own species, I know humanity only confusedly (it is an accidental property of humanity that it is my own species—this is true in the Aristotelian sense of "accidental" and probably also in the modern, since were I not to have existed, then I would not have been human). But I know humanity distinctly when I know it as rational animality, Aquinas thinks. Aquinas uses this distinction to solve the puzzle of how we can perform the Socratic task of seeking a definition for something, since we allegedly need a definition to know what we are seeking the definition of. The answer is that we only need to know confusedly what we are seeking the definition of.[note 1]
Of these, the third seems best to match Descartes' usage and I think it is a reasonable hypothesis that this is what Descartes has in mind. What is interesting, though, is that Aquinas will not tolerate Descartes' claim that we have a clear and distinct concept of God. For the essence of God is beyond our knowledge in this life according to Aquinas. Aquinas and Descartes agree that if we had the concept of God clearly and distinctly, we would know that God exists. But Aquinas denies the antecedent of this conditional (while accepting the consequent but on other grounds).
I wonder if Descartes' discussion of the clarity and distinctness of the concept of God doesn't commit a certain fallacy. In Aquinas, the concept of confusion is not a pejorative concept. The philosopher knows all things—but confusedly, at least in sense (2) (the philosopher knows general descriptions under which all things fall). There is no cognitive failing in knowing things confusedly. In fact, knowing things confusedly can be a cognitive achievement. To see the trees is distinct knowledge, while to see the forest is confused knowledge in sense (1)—but this confused knowledge is an achievement. In sense (2), our ability to abstract things is what gives rise to confused knowledge, and this confusion is an achievement. In sense (3) it is a bit harder to see the confusion as an achievement, but it is. For it is one thing to know that humanity is rational animality, and another to know that it is my species (I am not sure Aquinas would see it this way). One can know the former without knowing the latter, and so the latter confused knowledge is an achievement in part independent of the distinct knowledge.
The fallacy I am thinking of is that I get the feeling at times that for Descartes "confusion" is pejorative (just as it is in 21st century English). Now, then, Descartes may be having the following intuition behind thinking that the concept of God is not confused: Were the concept confused, there would be something wrong in us for having it—but to have the concept is surely a positive intellectual attainment. But if we see that there is nothing negative about having a confused concept of God (though in some ways it would be better to have a distinct one), then it becomes much easier to just that our concept of God is confused.
One reason to think Descartes would take "confusion" in a pejorative sense is that apparently it did have that valuatively negative sense in 17th century French (at least the 1694 French dictionary I have on my PDA gives only valuatively negative examples under "confusion").