Axiological Explanation

Definition

An axiological (value-based) explanation accounts for a fact not by identifying what produced it but by showing it is optimal among the competing possibilities. Nicholas Rescher's "Law of Optimality" holds that "value... enjoys an existential bearing, so that it lies in the nature of things that (one of) the best of available alternatives is realized." This explanation is not causal in the ordinary efficient-cause sense — value doesn't push or produce, it "eliminates" rival possibilities from real contention, leaving the best one standing.

In the Book

Rescher opens Chapter 11 by endorsing Kant's argument that an all-encompassing causal explanation of "reality-as-a-whole" is impossible: every factual explanation needs prior factual premises, so a "totalitarian" account of everything would hit either a vicious regress or a vicious circle. Rather than concede defeat, Rescher proposes shifting "the framework of explanation from the descriptive/factual order of explanation to the normative/axiological order." His "axiogenetic optimality principle" states that "in the virtual competition for existence among alternatives it is the comparatively best that is bound to prevail" — so "things exist, and exist as they do, because this is for the (metaphysically) best."

Rescher is explicit that this doctrine is itself only a contingent fact, not a logically necessary one — but he closes the loop by applying his own principle reflexively: the Law of Optimality explains itself, because it being the operative law is itself for the best. He also insists optimalism doesn't require theism (it doesn't presuppose a valuer who chose the best option, only that "order seeking" and "value seeking" in nature don't need an orderer or a valuer behind them) and that it explains not just that something exists but what character existence has, with a single unified answer — "this is for the best" — where accounts built on necessary-but-uncharacterized existence would need two separate explanations.

Why It Matters

Axiological explanation offers a third mode of "why," alongside efficient causation ("what produced this") and logical necessity ("this had to be so"): "this is the best of the live alternatives." That framing is exportable well beyond metaphysics — it's the implicit logic behind evolutionary optimality arguments, market-selection explanations ("this design won because it out-competed the alternatives"), and any account where the explanation for why X obtains is that X was the best-performing option in a real competition, without claiming anyone chose it or caused it to win by force.