all values of such a possible variable in its data. It is therefore clear that not only is such a functional relation as was originally described utterly valueless and incapable of affording any final information about the Universe, but that it cannot in any sense be significantly applied to the Universe at all; for as soon as we attempt thus to apply it, it ceases to be such a relation, losing all meaning with the disappearance of the variables. If, as we have suggested, the Universe is made up of active individuals, the reason for this result is clear; for no individual can be completely described in general terms, seeing that he is an individual, and consequently his actions cannot be so described.
The data e1, e2 ... en are referred to as 'determinants' of the system, the state of which is defined at any instant by the functional relation given. A 'mechanical' system is then appropriately defined as one having a purely material set of determinants, such as the position at given instants of certain pieces of matter. It is maintained that such a system might equally well be teleological (that is, purposive) or not. But the existence of purposes implies the existence of active individuals such as ourselves. Now we have seen that such a functional relation as defined above cannot exist in any adequate application to a Universe containing unique individual selves. Therefore, if a mechanical system can be described by such a functional relation, as it assuredly can if the terms 'mechanism' and 'matter' have their usual meaning as employed in the physical sciences, it cannot also be a teleological system, namely, one in which actions are purposive. Conversely, for the same reasons, no teleological system can also be mechanical.
It is then urged against the notion of efficient causality that the future determines the present to the same extent as does the past; in other words, cause does not 'compel' effect, in some sense in which effect does not compel cause.[1] But, again, this determination of the present by the future is only logical and descriptive. Even assuming for the moment that certain functional relations actually subsist which are significant as a complete or partial description of such a Universe as ours, there
- ↑ B. Russell, Knowledge of External World. Lect. VIII, p. 220.
