The interventionist model thereby avoids a simple-minded holism that merely asserts that many things are relevant without specifying which are causally efficacious.

In part because of these issues, that levels in psychiatry are not Marrian, Campbell (2006) argues for an interventionist approach to causation. This is the view that when we say X is a cause of Y we are saying that intervening on X is a way of intervening on Y (Woodward and Hitchcock 2003, Woodward 2003, Pearl 2000): manipulating one variable makes a difference to another. This is not a reductive analysis of causation, since it makes use of causal ideas—it just states that questions about wheth