Abstract
Many cosmological arguments for the existence of a first cause or a necessary being rely on a premise which denies the possibility of an infinite regress of some particular sort. Adequate and satisfying support for this premise, however, is not always provided. In this paper I attempt to address this gap in the literature. After discussing the notion of a causal explanation (section 1), 1 formulate three principles which govern any successful causal explanation (section 11). 1 then introduce the notions of a caused being, a causal network, and a causal chain, and argue that (roughly) an infinite causal chain cannot be explained merely by reference to the causal activities of the members of that chain (section 111). In a sequel to the present paper, I employ this result to construct two closely related arguments for the existence of a necessary being.