Science, in its attempt to extend the concept of causal determination over the whole domain of existence, has naturally felt these anthropomorphic implications as obstacles. From the effort to expel them arises what we may call the common scientific view of causation, as ordinarily adopted for the purposes of experimental investigation and formulated in the works of inductive logicians. The concept of a thing, except as the mode of interconnection of states, being unnecessary for the sciences which aim simply at the reduction of the sequence of occurrences to order, the notion of causation as a transaction between two things is replaced in the experimental sciences by the conception of it as merely the determination of an event by antecedent events. Similarly, with the disappearance of things as the vehicles of causal processes falls the whole distinction between an active and a passive factor. As it becomes more and more apparent that the antecedent events which condition an occurrence are a complex plurality and include states of what is popularly called the thing acted upon as well as processes in the so-called agent, science substitutes for the distinction between agent and patient the concept of a system of reciprocally dependent interacting factors. These two substitutions give us the current scientific conception of a cause as the “totality of the conditions” in the presence of which an event occurs, and in the absence of any member of which it does not occur. More briefly, causation in the current scientific sense means sequence under definitely known conditions. Indispensable as this notion of the determination of every event by a definite collection of antecedents and by nothing else is for practice, regarded as a logical formulation of the principle of the systematic unity of existence, it is open to grave objections, most of which will be found to have made themselves felt in the logic of the inductive sciences quite independently of conscious metaphysical analysis. In dealing with these difficulties, we shall find that their general effect is to place us in the following dilemma. If we wish to state the causal principle in such a way as to avoid manifest speculative falsehood, we find that it has to be modified until it becomes identical with the principle of Ground and Consequence in its most universal form, but as thus modified it is no longer of any service for the purposes of the experimental sciences. You seem driven to take it either in a form in which it is true but practically useless, or in one in which it is useful but not true. To illustrate the way in which this dilemma arises, we may examine three of the main problems which have actually been created by the scientific use of the principle,—(_a_) the puzzle of continuity; (_b_) the puzzle of the indefinite regress, (_c_) the puzzle of the plurality of causes.