According to John S., when we say "The function of the heart is to pump blood," we really mean "The heart pumps blood, and I think this is a good thing."
(we; say; The function of the heart) (I; think; this is a good thing) Context(I think,List([123, 130))):(this; is; a good thing)
I think,List([123, 130))
we I this
say think is
The function of the heart
this is a good thing
a good thing