PROP. LIV. The mind endeavours to conceive only such things as assert its power of activity.

Proof.—The endeavour or power of the mind is the actual essence thereof (III. vii.); but the essence of the mind obviously only affirms that which the mind is and can do; not that which it neither is nor can do; therefore the mind endeavours to conceive only such things as assert or affirm its power of activity. Q.E.D.