This understanding of truth is crucial to the evolution of Chan teachings, and to the apparent embrace of such contradictory claims—sometimes made by the same teacher—as that Chan involves the realization of “one mind” or “ordinary mind” or “no-mind”. Chan teachings are—at least ideally—improvised in effective and always situated response to actual needs and concerns. That is, they are exemplifications of the bodhisattva exercise of upāya or responsive virtuosity, not final expressions of eternally or universally valid insights.