> This is because legal people want something to exist that does not physically exist.

No law exists "physically".

Otherwise: Even in Computer Science the situation is more complicated, as is explained in the linked articles). Relevant excerpt from the first linked article:

"Child pornography is an interesting case because I find myself, and I think many people in the computing community will find themselves, on the opposite side of the Colourful/Colour-blind gap from where I would normally be. In copyright I spend a lot of time explaining why Colour doesn't exist and it doesn't matter where the bits came from. But when it comes to child pornography, I think maybe Colour should make a difference - if we're going to ban it at all, it should matter where it came from. Whether any children were actually involved, who did or didn't give consent, in short: what Colour the bits are. The other side takes the opposite tack: child pornography is dangerous by its very existence, and it doesn't matter where it came from. They're claiming that whether some bits are child pornography or not, and if so, whether they're illegal or not, should be entirely determined by (strictly a function of) the bits themselves. Legality, at least under the obscenity law, should not involve Colour distinctions.

[...]

The computer science applications of Colour seem to be mostly specific to security. Suppose your computer is infected with a worm or virus. You want to disinfect it. What do you do? You boot it up from original write-protected install media. Sure, you have a copy of the operating system on the drive already, but you can't use that copy - it's the wrong Colour. Then you go through a process of replacing files, maybe examining files, swapping disks around and carefully write-protecting them; throughout, you're maintaining information on the Colour of each part of the system and each disk until you've isolated the questionable files and everything else is known to be the "not infected with virus" Colour. Note that developers of Web applications in Perl use a similar scorekeeping system to keep track of which bits are "tainted" by influence from user input.

When we use Colour like that to protect ourselves against viruses or malicious input, we're using the Colour to conservatively approximate a difficult or impossible to compute function of the bits. Either our operating system is infected, or it is not. A given sequence of bits either is an infected file or isn't, and the same sequence of bits will always be either infected or not. Disinfecting a file changes the bits. Infected or not is a function, not a Colour. The trouble is that because any of our files might be infected including the tools we would use to test for infection, we can't reliably compute the "is infected" function, so we use Colour to approximate "is infected" with something that we can compute and manage - namely "might be infected". Note that "might be infected" is not a function; the same file can be "might be infected" or "not (might be infected)" depending on where it came from. That is a Colour.

[...]

Random numbers have a Colour different from that of non-random numbers. [...]

Note my terminology - I spoke of "randomly generated" numbers. Conscientious cryptographers refuse to use the term "random numbers". They'll persistently and annoyingly correct you to say "randomly generated numbers" instead, because it's not the numbers that are or are not random, it's the source of the numbers that is or is not random. If you have numbers that are supposed to come from a random source and you start testing them to make sure they're really "random", and you throw out the ones that seem not to be, then you end up reducing the Shannon entropy of the source, violating the constraints of the one-time pad if that's relevant to your application, and generally harming security. I just threw a bunch of math terms at you in that sentence and I don't plan to explain them here, but all cryptographers understand that it's not the numbers that matter when you're talking about randomness. What matters is where the numbers came from - that is, exactly, their Colour.

So if we think we understand cryptography, we ought to be able to understand that Colour is something real even though it is also true that bits by themselves do not have Colour. I think it's time for computer people to take Colour more seriously - if only so that we can better explain to the lawyers why they must give up their dream of enforcing Colour inside Friend Computer, where Colour does not and cannot exist."

Too much discussion of the XOR swap trick