But the essence of reason is nought else but our mind, in so far as it clearly and distinctly understands (see the definition in II.xl.note.

ii.); therefore (II.

xl.) whatsoever we endeavour in obedience to reason is nothing else but to understand.

Again, since this effort of the mind wherewith the mind endeavours, in so far as it reasons, to preserve its own being is nothing else but understanding; this effort at understanding is (IV.xxii.

Coroll.) the first and single basis of virtue, nor shall we endeavour to understand things for the sake of any ulterior object (IV.