Supervenience

Supervenience is a relation of dependence without reduction: one set of properties supervenes on another when there cannot be a difference in the supervening properties without a difference in the base properties. The mental supervenes on the physical if any two physically identical organisms must also be mentally identical — even if mental properties cannot be reduced to or identified with physical properties.

The concept was introduced into analytic philosophy by Donald Davidson and has become central to debates about the mind-body problem, moral realism, and metaphysical dependence. Supervenience promises the rigor of a mathematical relation (it is formally similar to covariance) while avoiding the stronger — and often implausible — claim that the supervening domain is nothing but the base domain.

The deepest problem with supervenience is that it is too weak to do the explanatory work philosophers often demand of it. Knowing that the mental supervenes on the physical tells us that mental differences require physical differences, but it does not tell us *why* they do, or *how* the physical produces the mental. In this respect, supervenience is a descriptive relation masquerading as an explanatory one. It marks the boundary of our current understanding without crossing it.

The relation between supervenience and grounding remains contested. Some philosophers treat supervenience as a symptom of grounding: if A supervenes on B, then A is grounded in B. Others argue that supervenience and grounding are independent relations, and that the former can hold without the latter. This debate is inseparable from the broader question of ontological dependence and the architecture of fundamentality.