2. Those who deny the privilege of living well to plants, because these
lack sensation, are not on that account obliged to grant it to all
animals. For, if sensation consist in the knowledge of the experienced
affection, this affection must already be good before the occurrence of
the knowledge. For instance, the being must be in a state conformable
to nature even though ignorant thereof. He must fulfil his proper
function even when he does not know it. He must possess pleasure before
perceiving it. Thus if, by the possession of this pleasure, the being
already possesses the Good, he thereby possesses even well-being. What
need then is there to join thereto sensation, unless indeed well-being
be defined as sensation and knowledge (of an affection or state of the
soul) rather than in the latter affection and state of the soul itself?