"Teleology is not the antithesis of causality, but subordinate to it. It is, of course, inadmissible to consider "final causes" as implying that an object or end is capable of having effect. No event that has not yet taken place can possibly act. But results are caused by the keeping of the end in view, and it is in this way that the final becomes an efficient cause. These final efficient causes are not in the slightest degree metaphysical, for they derive from organic matter."