Summary
Depth ontology is the philosopher Roy Bhaskar’s claim that reality has layers, and that what we observe is only the top one. In ‘A Realist Theory of Science’ (1975), the founding text of what became critical realism, he set out three nested domains. The empirical is what people experience. The actual is everything that happens, noticed or not. The real contains both, plus the structures and causal powers that produce events.
Those powers exist even when nothing triggers them: a match can light whether or not it is ever struck. Bhaskar’s target was empiricism, which admits only what can be experienced and so collapses the three domains into one.
Rationale
Bhaskar’s causal powers are real even when unexercised, close to what philosophers call a disposition. Ours likewise show only in what they make “feel more intuitive or self-evident”, though his word ‘mechanism’ is too machine-like for us.