Eh...?

Watching a cup break... or paper be torn, for instance...

Would anyone feel pain from that?

Wood splitting, worms squirming,

animals dying... Around that point—

Before coming all the way here, most people don't know unpleasantness at all...

...That is to say, empathy for pain

and the recognition of others' emotions

only occurs among a class of beings close to oneself... or to put it the other way around:

To feel unpleasant about something

is to learn what one truly is.