The suggestion was purely theoretical, since we have no means of carrying it out.
Advanced English Dictionary
+adjective[usually before noun] 1 concerned with the ideas and principles on which a particular subject is based, rather than with practice and experiment: a theoretical analysis / approach / debate / model + theoretical physics + The first year provides students with a sound theoretical basis for later study. Antonym: EXPERIMENTAL, PRACTICAL 2 that could possibly exist, happen or be true, although this is unlikely: It's a theoretical possibility. theoretically adverb: theoretically sound conclusions + It is theoretically possible for him to overrule their decision, but highly unlikely.
Collocation Dictionary adj
be | remain
highly | purely
This research is purely theoretical.
| largely | rather
Random quote: Man is not sum of what he has already, but rather the sum of what he does not yet have, of what he could have.: Jean-Paul Sartre