Leibniz is one of my favorite philosophers, tempering excessive philosophical ambition with admirable moral sensitivity. His sensitive side stems, in part, from his commitment to what is known as the praejudicium Leibnitii: "If I were wrong, I would like to err in favor of other persons, and not be mistaken to their disadvantage." His ambition stems, in part, from his mad and unrelenting commitment to the principle of sufficient reason (PSR): "no fact can be real or existing and no statement true without a sufficient reason for its being so and not otherwise." This is a mischievous principle. Parmenides used it to argue that nothing changes; Aquinas, to argue that God exists; Spinoza, to argue that nothing is contingent. No tenet of common sense seems able to escape PSR's withering gaze.
One might have doubts about whether PSR is true, either because it seems to conflict so drastically with common sense or because there seem to be some facts that are just brute (think quantum indeterminacies). What interests me, however, is not so much whether PSR is true as the ideal of which PSR seems to be a manifestation. I've been thinking about the ideal of sufficient reason, pursuit of which demands that reason until there can be no more reason. This is a tempting ideal. Its pursuit fuels the regress argument from epistemology, requiring any justified belief to have its justification grounded in some reason, which in turn is grounded in some further reason, and so on. If there are no endless regresses of justification-giving reasons, pursuing the ideal vindicates epistemological foundationalism (or skepticism!).
Metaphysics, too, is no stranger to the ideal. Reality that accords with the ideal of sufficient reason requires any existent to have its reality grounded in some reason, which in turn is grounded in some further reason, and so on. If there are no endless regresses of reality-giving reasons, pursuing the ideal vindicates either metaphysical foundationalism (where the basic entities have no deeper reason) or nihilism (where there is no foundation and therefore no reality).
Pursuing the ideal of sufficient reason produces structures (epistemological, metaphysical, or otherwise) that are asymmetric, because what is a reason for something cannot have that something as its reason (whence the ban upon "circular" reasoning).
Given the ideal's prevalence and attraction, I've been wondering whether there are any alternative ideals one might pursue in the philosophical quest for understanding the world's structures (be they metaphysical, epistemological, or something else). Philosophers from the Chinese tradition seem to pursue a different ideal, the ideal of the round. Pursuit of this ideal demands inclusion until there can be no more inclusion. An ideally inclusive structure differs from an ideally rational structure, because the structure of inclusion is not asymmetric. For example, if a baseball team is ideally round, the team includes each of its members and each member includes the team; and if a system of justified beliefs is ideally round, each belief includes every other as part of its justification.
I'm currently working on tracing the consequences commitment to the ideal of the round has for metaphysics. My hunch is that a reality that accords with the ideal of the round has a holistic, rather than a linear, structure, offering a satisfactory alternative to metaphysical foundationalism. I'll report back with progress on how this hunch is playing out, as well as more information about the ideal of the round.
For now, though, I'm wondering: Are there examples, from politics, ethics, aesthetics, or wherever, in which the ideal of sufficient reason manifests itself? Well-known arguments with structures analogous to the epistemological regress argument?