With a bit of mindfulness practice (shamatha/vipashyana)—“the quiescent basis for peace and all higher knowledge”—we train the “wild horse of the mind” to choose positive mental/ emotional states. We learn to awaken to the original noetic purity of our primordial awareness ground of being as it arises unbidden, then spontaneously displays through our ordinary, “primordially pure” direct perception, prior to conceptual elaboration and judgment. So it is, happiness is fundamentally a skill set. Here, naturally, effortlessly arises our bodhicitta, the intention/action to benefit all beings. For Mahayana, such a lifestyle results in liberation from suffering, and is the very cause of human happiness, both relative—the human flourishing of eudaemonia, felicitas—and the ultimate/spiritual happiness of mahasuka, paramananda, beatitudo.
We live in these two worlds—relative and ultimate—at once! Is not our soteriological happiness imperative the recognition, realization, then compassionate expression of the prior and present unity of these, our two human faces? To conceptually reduce numinous nondual Ultimate Truth to dualistic Relative-Conventional Truth, or not to reduce, that is the urgent question of liberated human awareness, and of scientific reductionism. This is the yoga. Hence verily, from the epistemology you choose, arises the metaphysical ontology you deserve.