Supervenience - Wikipedia
Supervenience (Stanford Encyclopedia of Philosophy)
A set of properties A supervenes upon another set B just in case no two things can differ with respect to A-properties without also differing with respect to their B-properties. In slogan form, “there cannot be an A-difference without a B-difference”.
As we shall see, this slogan can be cashed out in many different ways. But to illustrate the basic idea, imagine that there is a perfect forger. Her copies of paintings not only fool the art dealers, but are in fact exact duplicates of the originals down to the precise placement of every molecule of pigment—indeed, down to every microphysical detail. Suppose that she produces such a copy of El Greco’s A View of Toledo. It is of course different from the original in various respects—it is a forgery, it was not painted by El Greco, it is worth quite a bit less at Sotheby’s, and so forth. But the forgery is also exactly like_the original in other respects. It is the same shape, size, and weight. The surface of the canvas contains the same arrangements of colors and shapes—a blue rectangle here, a green swirl there. Indeed, it _looks just the same, at least to a single viewer under identical lighting conditions and so forth. Perhaps it is even just as beautiful as the original, though that is more controversial.
The properties that the forgery is guaranteed to share with the original are those that supervene upon its microphysical properties. Two paintings that are microphysically just alike are guaranteed to be just alike in the arrangement of colors and shapes on their canvases. That is, you cannot change the arrangement of colors and shapes on a painting’s canvas without changing its microphysical properties. This is just to say that the arrangement of colors and shapes supervenes on its microphysical properties.