 Yogācāra’s impressions-only theory and the Sautrāntika’s representationalist theory both explain our sensory experience (the spatio-temporal determinacy, intersubjective agreement, and causal efficacy). They agree on what the observables are: mental entities, including mental images but also emotions such as desires. They also agree that karma plays vital role in explaining our experience. The realist theory, though, according to Dignāga’s Investigation About the Support of the Cognition (Ālambanaparīkṣāvṛ tti [ĀlamPV]) has to posit the reality of additional physical objects, things that are in principle unobservable, given that all we experience in the cognition are our impressions ([ĀlamPV], Tshad ma ce 86a).