Dublinpilot, assuming that you mean a passenger without
a valid, current license.
Yes, but you are still the pilot of the aircraft, totally
responsible for anything that happens as a result.
So where you might well let a sensible, trusted passenger
try out some gentle turns back and forth at a good height,
well away from traffic and airspace. It would be a fool
hardy pilot who let a passenger attempt a landing.
It would certainly make an interesting insurance claim!
-- Andrew