Existence as Causal Participation

Existence as Causal Participation

We need a criterion for existence that applies uniformly across scales—here "we" means anyone trying to think clearly about this.

The criterion I adopt is this: an entity $X$ exists at scale $\sigma$ if and only if

That is, $X$ takes and makes differences at scale $\sigma$. It participates in causal relations at that scale.

Example.

• An electron exists at the quantum scale: it takes differences (responds to fields) and makes differences (affects measurements).
• A cell exists at the biological scale: it takes differences (nutrients, signals) and makes differences (metabolism, division, death).
• An experience exists at the phenomenal scale: it takes differences (sensory input, memory) and makes differences (attention, behavior, learning).

This is closely aligned with IIT’s foundational axiom: to exist is to have cause-effect power. But we extend it: cause-effect power at any scale constitutes existence at that scale, with no scale privileged.