Most laws concern subjects that exist.  This is not, however, strictly necessary.

The most obvious example of this is the language of the Fundamental Contract and the Imperial Charter which consistently refers, when discussing the fundamental and civic rights, the requirements for citizen-shareholdership, and so forth, the word darav, “sophont”, which lies at the heart of our modern polyspecific society.  It is often less obvious than it should be to the modern student that at the time of writing, the eldrae were a worldbound species, with cladism, exotics, and artificial intelligence not merely centuries but millennia in the future.

The reasoning behind this choice has been, unfortunately, lost in time and unrecorded negotiations – and while it would be pleasant to imagine such tremendous foresight on the part of the Founders, we might perhaps more reliably credit fading hopes for the legendary mythologae and some of the wilder scribblings of the era’s fabulists and constructors of clockwork automata instead.

Another example, which pertains not merely to things which don’t exist but things which, it is generally believed, can’t exist, is the Causal Weapon and Editorial Time Machine Act (4110).  While the universe as we know it is block, and as such not susceptible to paradox or retroactive change from commonly known time-travel effects such as relativistic travel, closed timelike curves via wormhole, and acausal logic processors, this Act exists against the possibility that the generally accepted theories of temporal mechanics are incorrect and that methods of time travel exist which do not obey the Chronological Consistency Protection Theorem.  To summarize, the Causal Weapon and Editorial Time Machine Act provides for a preemptive, preventative, and summary death penalty to be applied to anyone constructing a time machine capable of retroactive change – except under highly controlled local experimental conditions for the purpose of testing the Theorem – upon charges of attempting the massively parallel cognicide of every sophont within the eventual light-cone of their destination when.

This is also an example of a law which would be very difficult to apply if the crime in question were actually to be committed.

– Ephor Valarian Elarios-ith-Elarios, “Lectures”