Is similarity a universal?

Question

Is similarity a universal?

Answer 1

Now you're cooking.  This is an awesome example of a universal because it already does not have a physical (nor emotional) component to work with.  Yet, every man from every land knows (intrinsically!) this concept.

WHERE DOES IT COME FROM???

Answer 2

Entities X and Y are similar iff there is some universal property that they share.

Now this might be true, but does it does not seem to be very helpful as a criterion for determining when we've got a universal property.  The problem is that similarity abounds.  Take any two physical objects whatever; there are countless ways in which they are similar.  So, how do I know when they are similar and when not?  Can I say that they are similar insofar as they share the same property?  Yes, but this presupposes that we know when a "property" is possessed and when it isn't, and it assumes that we have already determined when we can say something is a property and when not.   But this is what we are trying to establish.  Can we say that things are similar insofar as the same predicate truly applies to both?   If so, we are back at the criterion that every meaningful predicate determines a property, and this, we have seen, generates paradox.