wanted a term with a more general sound. 'There is an _X_', he wanted to
say, 'which scholasticism has defined as substantial form, but I am going
to give a new definition of it.' Entelechy was a useful name for _X_, the
more so as it had the authority of Aristotle, the master of scholasticism.

Under the name of entelechy Leibniz was upholding the soul of [14]
scholastic doctrine, while retrenching the limbs and outward flourishes.
The doctrine of substantial form which he learnt in his youth had had
_something_ in it; he could not settle down in the principles of Descartes
or of Gassendi, because both ignored this vital _something_. Since the
requirements of a new science would not allow a return to sheer
scholasticism, it was necessary to find a fresh philosophy, in which
entelechy and mechanism might be accommodated side by side.

If one had asked any 'modern' of the seventeenth century to name the
'ancient' doctrine he most abominated, he would most likely have replied,
'Substantial form'. Let us recall what was rejected under this name, and
why.

The medieval account of physical nature had been dominated by what we may
call common-sense biology. Biology, indeed, is the science of the living,
and the medievals were no more inclined than we are to endow all physical
bodies with life. What they did do was to take living bodies as typical,
and to treat other bodies as imperfectly analogous to them. Such an
approach was _a priori_ reasonable enough. For we may be expected to know
best the physical being closest to our own; and we, at any rate, are alive.
Why not argue from the better known to the less known, from the nearer to
the more remote, interpreting other things by the formula of our own being,
and allowing whatever discount is necessary for their degree of unlikeness
to us?