Abstract

Emergentists hold that higher-level phenomena are something ‘over and above’ the sum of their most basic parts. Typically, this involves the claim that emergent phenomena are both distinct from and novel with respect to the base phenomena from which they emerge, whilst nevertheless being dependent upon the base phenomena. A popular way to characterise strong metaphysical emergence is to hold that emergent entities must possess novel causal powers. Underlying this trend is a commitment to ‘Alexander’s Dictum’, which can be roughly glossed as the claim that to exist is to have causal powers. Alexander's Dictum, however, does not enjoy universal assent. Nor is it clear exactly how the rough gloss of the principle ought to be finessed. This paper examines the role the principle plays in the debate between emergentists and reductionists; the motivations for endorsing it; criticisms which it faces, and responses to these criticisms. It argues that whilst these criticisms may show that Alexander's Dictum cannot be endorsed as a fully general principle, nevertheless, it can be formulated in manner that makes it suitable for use in the emergence debate. Finally, some wider consequences of giving causal powers a central role in the debate between emergentists and reductionists are examined.