I'm sure that you're probably enrolled in Transfiguration. in the very first lesson, you learned about Gamp's Laws of Elemental Transfiguration. But I bet you never realized that one particular group of spells could possibly violate one of the laws. These are duplication spells. Since these spells conjure new objects, they fall under that umbrella definition of Transfiguration you probably learned a few weeks ago. For this example, we'll just use Geminio.

Geminio creates copies of the target (whatever your wand is aimed at), all indistinguishable from the original. You can probably guess where this is going.

So, we have in our hands a spell that can create identical copies of anything. Let's try it on a mouse, just to see what happens. If we assume that only Gamp's law is true, then we probably won't be able to copy the mouse.

Now, pretend that we can ignore Gamp for a few moments. We copy the mouse, and we're left with a dozen mice running all over the room. According to the description of the spell, each of the eleven copies should be indistinguishable from our original mouse.

Okay, turn Gamp back on. If the law is correct, then there will be something wrong with eleven of the mice, which will probably leave them dead. But, this one flaw means that those eleven mice are not accurate copies of the originals. Thus, the premise (description) of the spell is false

Muggles have determined that there are five qualities that every living thing has. I won't go into much detail here, but one of these qualities is the ability to reproduce.

Even if our dozen mice all look and act the same, we can test whether the copies are truly alive or not by adding a female in heat to the group. If the copied mice were alive, they should pursue the female and try to mate with her. Even if the female rejects every single one of the copies, they are still alive, as they all had the ability to reproduce.

Unfortunately, this doesn't explain what happens if the copies did not persue the female mouse. Perhaps wizards may one day find the answer.