By this argument, 95% of the dictionary is acceptable in a fantasy world. For example 'television', 'microscope' and 'photograph' have Greek/Latin roots.
So what?
An ancient Greek probably would have said of someone who had the ability to see over the horizon that he had "television" or something close to that. The word would be the same as our term for the modern entertainment/informational tool that has become nearly ubiquitous, but its
fundamental meaning is different.
That happens with words- they accrue different meanings over time.
After all, is the torch of 300 years ago the same as one you'd find in a British hardware store?
The term 'psionics' was invented by the editor of Astounding Science Fiction, John W Campbell.
No argument, but again, its merely words. The concepts behind the powers themselves are old as dirt...is that really weighty enough justification for tossing the sub-system?
If so, what if the game's designers called Psionics Psychic Powers? (Again, given the nature of the sciences of the 13th-16th centuries, the names of the powers described might be as they are- latinate or of greek origins.)
The concept isn't different enough from magic to justify a separate system.
I disagree...to a point.
The psychic- by any other name- generally sources his power from within. He is exercising his mind over matter directly- often his own matter- without arcane formulae, the intervention of spirits or powerful beings, tapping into pools of mana, etc.
As stated above, there are dozens if not hundreds of theories of magic in RW legend, myth and fiction, each with their own- sometimes contradictory- rules. The magical methods of the animist shaman isn't the same as the runecaster, the elementalist, the hermetic wizard, the hedge wizard, the diabolist, the truenamer, the binder or even someone whose power waxes and wanes with some kind of natural rhythm...
And only the being who
directly manipulates raw magic (a spellshaper) knows that all are different pathways to the same kind of power.
What it
doesn't justify is that magic and psionics don't affect each other.