conceptual

  Similarity comes in degrees.  But belonging to a kind or sharing a property do not. Hence (from 1 and 2), similarity cannot be belonging to a common kind or sharing a property. Unless we (i) amend our conception of belonging to allow for degrees, or  (ii) we understand ‘being more or less similar’ as ‘having more or less properties or kinds in common.’ But (ii) requires kinds to be previous to similarity, (otherwise, the number of kinds in common would depend entirely on the number of objects involved in the comparison and not on their actual similarity).  Thus we must have at least some categories given a priori before comparison.   Psychological evidence backs this hypothesis up: Comparison is a combination of bottom-up and top-down cognitive and perceptual processes (Rehder and Hastie 2001) This raises two fundamental questions:  The genealogical question : where do these a priori categories come from?  Do they all come from the same ...

What is the relation between comparison and similarity? Here is a paradox: For philosophers like Kant, Frege and others, comparison allows us to gain knowledge about universals (properties or concepts) out of our knowledge of individuals. Hypothesis of common sense: comparison is a bona fide epistemological process, i.e. we learn things through comparison. But, what is to compare ? To compare is to take two things to see if they are similar (or not) and how. Thus, what we learn from comparing things is whether they are similar or not, and how.  Hence, before you compare two things, all you need to know about them is that they are different.  Therefore, you can, at least in principle, compare any two things that are different. But this would be a methodological nightmare!  Thus, we need some heuristics to determine what things are worth comparing. The obvious answer is that, in order for two things to be genuinely comparable they must be similar.  But how ...