Transcendental method vs. the internet blacklist bill(s)

Background
Okay, so there was this guy a while back named Immanuel Kant. He was pretty sharp. He said a lot of things, and a lot of them were wrong, and we don't really know which ones just yet. Anyway, one of the things he came up with is called "the transcendental method." The transcendental method is a way of learning new stuff based on the stuff we already know. The way we usually do this is through deduction, wherein we draw conclusions by synthesizing statements we know to be true. You can think of the transcendental method as a sort of reverse deduction, wherein we derive true statements from the conclusions we're able to observe (or otherwise accept as true).

The textbook example of deductive reasoning is "All men are mortal and Socrates is a man. Therefore, Socrates is mortal." An application of the transcendental method here, on the other hand, would look more like this: "Seeing that Socrates has died, I must infer that Socrates was mortal." Another way of saying this is that "Socrates being mortal is a condition of the possibility of Socrates having died." It seems a bit trivial on this level, but is actually a really useful reasoning tool.

Now, let's look at law. Laws essentially come in two forms – prescriptive and proscriptive. Prescriptive laws mandate certain acts/behaviors, while proscriptive laws prohibit them (legal scholars also like to claim that there are "permissive" laws that explicitly permit you to do things – a quick run through the POOP, however, reveals that a permissive law is simply a prohibition on prohibiting a given act/behavior). Similarly, acts/behaviors come in three flavors: impossible, possible, and necessary (this is cheating somewhat, since it is necessary for me to breathe only insofar as it is impossible for me to not breathe; but for rhetorical purposes here, the spectrum suits).