Ab is really the next term in the series of historical progress, our making it our end can neither help nor hinder its realisation. If, on the other hand, there is really a meaning in our making the world-end our own, then we cannot bring that end, the realisation of which is conceived as still in the future, under the category of efficient causality, and say with confidence that it is the next stage in the course of events. [Sidenote: 3. Difference between causality and teleology.] The idea does not work itself out in the same way as an efficient cause works in the processes of nature. We might indeed speak--perhaps with some intelligible meaning--of the tendency of evolution becoming conscious in man, and then working towards its own realisation as a fixed idea. So far as the simpler representations are concerned, this mode of action has been clearly illustrated in Mr Bain's writings; and the characteristic is not limited to the less complex kinds of mental objects. The idea is, in its own nature, a force tending both to exist in consciousness and to realise itself through the motor energies.[274] Consciousness of an end is a motive to action. Thus the notion of final cause includes that of efficient cause; but the two are not convertible. The idea of an end, being conceived by reason, cannot be described simply as a tendency become conscious. It has passed into the region in which various conceptions are, or may be, competing against one another, and the resultant is decided on upon grounds which may be called subjective since they proceed from conscious determination. However the laws of this conscious determination may be expressed, they are not to be identified with the natural sequence of events as it may be conceived to exist independently of the individual consciousness. What seems the tendency of things may be altered or modified upon some ground of preference by the conscious subject. In passing therefore to the working out of a rational or mental idea--such as is implied in the conception of an end--we can no longer fully represent our notions by means of the determined temporal succession called causality. [Sidenote: These notions unconnected by empiricism,]