3. From discussing a •psychophysical theory of pleasures
and pains I now turn to one that is •biological: still concerned
with organic states or events that accompany or immediately
precede pleasures and pains, it focuses not on •the actual
present characteristics of those states and events but on
•their relations to the life of the organism as a whole. I mean
the theory that ‘pains are the correlatives of events that are
·potentially· destructive of the life of the organism, while
pleasures are the correlatives of events that are preservative
of its welfare’. [Spencer starts little differently, but Sidgwick says that
‘destructive’ and ‘preservative’ adequately express what Spencer ends up
with.]