> THEN TAKE THE UNIVERSE AND GRIND IT DOWN TO THE FINEST POWDER AND SIEVE IT THROUGH THE FINEST SIEVE AND THEN SHOW ME ONE ATOM OF JUSTICE, ONE MOLECULE OF MERCY.

That's very naively materialist. Once you notice that, it becomes clear that the concepts mentioned are not "lies".

The passage may be trying to say something serious about those concepts not being universal, objective ones, but if it's intending to make a serious point it misses the mark.

But then again, it may not be intended to be taken seriously at all. Perhaps Pratchett assumed the weaknesses in this position would be obvious.

> Likewise, paper money

If someone writes an IOU to you, is that a lie? How about a check?