… sīla-paridhotā hi bho Gotama paññā, paññā-paridhotaṃ sīlam, yattha sīlam tattha paññā, yattha paññā tattha sīlaṃ. Sīlavato paññā paññāvato sīlaṃ, sīla-paññānañ ca pana lokasmin aggam akkhāyati. (Dīgha-Nikāya i. 123)
Or, if like me you can’t read a lick of Pāli:
… For understanding, Gotama, is washed around with virtue, and virtue is washed around with understanding. Where there is virtue there is understanding, and where there is understanding there is virtue. Those who have virtue possess understanding, and those who have understanding possess virtue, and virtue and understanding are declared to be the best things in the world. (translated by Keown, 2001, p. 39)
The point is that ethics, or morality – doing the right thing – is tied in with wisdom, insight, or philosophy. As Socrates stated, “To know the good is to do the good.”
What is the good? What is reality itself? These are questions of metaphysics.
Metaphysics: 1.the branch of philosophy that treats of first principles, includes ontology and cosmology, and is intimately connected with epistemology. (dictionary.com)Metaphysics first aims to be the most general investigation possible into the nature of reality, asking, “are there principles applying to everything that is real, to all that is?” The second aspect of metaphysics is its quest to uncover what is ultimately real, frequently offering answers in sharp contrast to our everyday experience of the world. For instance, the ancient Greek philosopher Thales suggested that water was all that was ultimately real, George Berkeley is famous for asserting that mind alone is real, while many contemporary thinkers believe that matter alone is real. Understood in terms of these two tasks, metaphysics is very closely related to ontology, which is usually taken to involve both "what is existence (being)?" and "what (fundamentally distinct) types of thing exist?"
To elucidate what Buddhist metaphysics may look like we may employ the trilemma introduced by Prof. Earnest Sosa (In The Oxford Companion to Philosophy, Honderich ed., p.559) of illusion, well-founded appearance, and fundamental reality. If we recall the three marks of existence: anicca, anattā, dukkha (impermanence, non-self, and unsatisfactoriness), then we can explain the Buddhist position on these three metaphysical levels of reality.
Illusion is obviously anything thought to have permanence, attā, or sukkha (satisfactoriness or unending happiness). To hold anything thinking, “I will have this forever” is to merely grasp illusion. To think to yourself, “this is my true self, this is who I am” is to create a boundary, an illusion. Even the view, “I am already enlightened” is an illusion. In fact the Buddha described the “conceit of I-am” (asmi-mana) as one of the most nefarious forms of ignorance. As Rupert Gethin clarifies, “Thus Buddhist thought suggests that as an individual I am a complex flow of physical and mental phenomena, but peel away these phenomena and look behind them and one just does not find a constant self that one can call one’s own.” (1998, p.139) Lastly, To strive for anything thinking it will bring unending happiness also is an illusion. Often, especially when we are young and ambitious, we think that reaching this goal or that will bring us happiness. And sure, we find happiness in reaching goals, but isn’t it always the case that our happiness is lost as we see yet another goal to strive for (thinking, “then I’ll really be happy.”). This is what psychologists today aptly call the hedonic treadmill. To get beyond mere illusion we must get beyond the ideas of permanence, of who we truly are – our true Self, and true happiness (in this world).
Well-founded appearance, it would seem, is represented in the various Abhidhamma accounts of dhammas. These are the essentials of experience: momentary, self-identical (svabhava), and caused. This is a move to a level of reality where spiritual growth can occur. It is in advanced vipassanā meditation practice that one moves his or her attention to the ever-changing flow of dhammas, to experience itself free of conceptual constructs – free of illusion. Of course, as any vipassanā teacher will tell you, this is based on a great deal of preparatory work, work done within the realm of illusion.
The final level, fundamental reality, is empty of its own qualities, but is itself the anicca, anattā, and dukkha quality of all dhammas. This may be better understood by referring again to Inada’s claim that the anattā doctrine represents a Copernican turn in philosophy. Whereas we would assume that metaphysical claims should come in the form of an assertion of an underlying reality, the Buddhist metaphysics points instead to everyday reality and says “this, this is fundamental reality.” There is no foundation beneath it to be found.
It thus becomes plausible to say that Buddhist metaphysics is an anti-metaphysics, insofar at it rejects abstract theorization and points instead back to the pragmatic aspects of meditation and ethics. Again, the metaphysics of Buddhism may be summarized as such: ultimate reality is nothing other than this reality seen correctly (yathabhutaṃ), this reality may be analyzed into constituent parts or dhammas, and it is from these dhammas that we, out of ignorance, construct the stories of our lives.
The therapeutic, or ethical, aspect arises when we truly come to terms with this understanding and its implications. The first step is in understanding that most of the big problems in life are illusions. War, poverty, disease, famine: all illusions. But they are based on well-founded appearances: instances of death, hunger, illness, and waste. Well-founded appearances are not themselves illusions: death is real, so is hunger and the rest. Yet it becomes illusion when it is seen as permanent, possessing self, and/or leading to ever-lasting happiness.
Seen correctly, as impermanent, not-self, and unsatisfactory, death, like life, takes on a new meaning. The two lose their mystique as opposites and we see that they are intermingling all of the time, just as wealth and poverty, disease and health, and so on are always commingling. Knowing this, it no longer makes sense to struggle so much for one and to avoid the other. Knowing this one lets go. One flows with life rather than against it.
 Kenneth Inada, “Problematics of the Buddhist nature of self,” Philosophy East and West, 1979, vol. 29, no.2, p.141.