Once More on Black Ravens
In spite of the fact that I consider my two previous posts on the "Raven paradox" to be correct as far as they go, I have still been drawn to this problem because I have not addressed a central issue: namely, how can enumerating non-black objects possibly prove that all ravens are black? To restate the issue, stating that "all ravens are black" is supposed to be logically equivalent to "all non-black objects are not ravens." Therefore, if I find a non-black object and ascertain that it is not a raven, I have, theoretically at least, contributed to proving that all ravens are black. This seems counterintuitive, since I haven't even seen a raven and yet I have somehow helped to prove that all ravens are black. Let's reduce the problem to marbles. There is a bin filled with marbles, some of which are translucent, which we will identify with "ravens," and some are opaque, which correspond to "not ravens." There are 100 marb...