[chongli]

The purpose of the system (the police in this casse) is what it does.

Nope. That's an ideology, not a statement of fact. It completely negates the possibility that systems can become corrupted (or simply fail) and no longer work towards their original purpose.

[arrowsmith]

"systems can become corrupted (or simply fail) and no longer work towards their original purpose"

Er, that's exactly what "the purpose of a system is what it does" means.

[chongli]

No, “the purpose of a system is what it does” implies that the original intent of the creators of a system was for it to become corrupted.

[arrowsmith]

That's one way to read the literal meaning of the words, but it's not what the phrase means as originally intended.

[chongli]

Right, but then we apply the phrase to itself and this is what we get!

[uoaei]

Nope. That's an imposition of metaphysics onto what is solely clearly mere empiricism.

[immibis]

Nope. You added that extra word "original" in there.