The criticism of the notion of cause is quite similar to that of the notion of substance. It is a notion necessary to the mind, for just as without substance there can be no mental connection between simultaneous phenomena, in the same way without cause there can be no connection between successive phenomena. Causality is the necessary law that connects each phenomenon with its anterior conditions. Without this law there could be no science, no induction, no experience. It cannot, consequently, be derived from experience, since it is the very condition of it. But do we seek to render cause objective as well as substance? If so, we must understand it in a different sense. Cause is no longer merely a phenomenon anterior to another, the antecedent of a consequent. It is something quite different, it is force, the active power, that initiates the movement, and of which we find the type in our own consciousness. Hence, to render cause objective is nothing less than to spiritualize the universe, to suppose everywhere causes similar to ours--it is a kind of universal Fetichism. And, further, we fall into the same difficulties as we did with regard to substance. Is there only one cause or many causes? Lastly, causation thus understood is of no use whatever to science, for science has no need at all of metaphysical forces, that which is necessary to science, and employed by it under the name of force, being a measurable quantity which it disengages from phenomena and from experience.