The classical discipline is the same. Socrates holds a definition at arm's length until it breaks; Epictetus guards the governing faculty so that no single impression is granted assent before it is examined. Both are technologies for preventing the mind from becoming trapped in its first map.
Parallel thinking extends that discipline into the technical register. It says: keep two honest maps alive, know what each one costs, and let the object decide which one survives contact. The only disorder is a disordered mind. The rest is material that a sufficiently ordered set of coordinates can work with.
Parallel thinking is not believing two things at once. It is refusing to believe one thing before the other maps have had their turn.