1. They are materially distinct from originals
2. They are the formal effects of originals (or originals are formal causes of copies)
3. They are logically associated
4. They resemble each other
I disagree with all of these criteria because I think there are counter examples to all. Let's start with the first. There are many ways to understand this. If I understand this first criteria correctly, it means something like a copy cannot be made of the same stuff or material as the original. Or it could just mean that they are not numerically identical meaning they just have to be at least two different things instead of one. I agree with the last interpretation but I think the first faces serious problems. For example, a statue made of clay can be destroyed by crushing it into a ball and then the ball may be fashioned back into the form of the statue. It seems to me that the statue was destroyed when it was crushed and that the subsequent sculpting of a statue from that same piece of clay is a copy even though it is made of the same piece of clay and may resemble it in form.
The second criterion faces the counter example I gave of causal loops showing that a painting e.g., may be the copy of another painting which in turn was a copy of it. I also gave the example of Eternal Recurrence which is supposed to show that there can be originals "all the way down" a causal line. These example also show that 3 cannot be true (if I understand 3 to mean that they are conceptually analytical of each other) because it shows that copies can exists independently of any original and an original can be caused by some earlier work which is also an original and that the two works are similar in resemblance to each other and materially distinct (either in the numerical or the made-of-the-same-stuff sense.
Finally the last criterion of resemblance "to a high degree" is problematic for the reason that there can be bad copies. I think most people have had the experience of using a copy machine only to have the copy turn out looking nothing like the original in that there were distortions, color changes, missing parts, etc. We can either call these copies "failed copies" or "bad copies." If they are bad copies as I think they are and not failed copies, it would be problematic for that criterion. The vagueness of "resemblance to a high degree" is also not desirable for the definition. Things may resemble on indefinite number and degree of criteria to something else. Resemblance is also perspective sensitive. For example, two photos may look very similar to one individual A and very different to another person B because the photos may have different saliently colored regions and if A is color blind, she will only see different shades of gray in those regions while A will see completely different colors and thus think the two photos not resemble.
I gave an alternative definition of copy as follows:
Object A is a copy iff its creation was intended as a copy of some object B (or maybe even an idea of such an object) and A does not (numerically) equal B.
I don't think this definition is susceptible to the counter examples but it may have its own problems. Consider DNA. DNA are copies of other DNA molecules and yet there was no intention in nature to copy (despite what IDers like to think).
Are DNA copies? Well yes. But I think there is an ambiguity in the word copy. Copy, as it is used for art and technology and writing etc, mean something different than copy in nature perhaps. The definition I gave is for copy in the former context while the later for copy in nature is more of a metaphorical usage of copy. I think paying attention to this difference in usage will not render my intentional definition problematic.
