If we are empathetic, capable of being aware of other people's feelings, it is reasonable that the memories attached to awareness exist not isolated in the individual but across people.
You should look up mirror neurons.
Aside from those we definitely do not know other people's feelings, though. I think that's obvious from the amount of conflict coming from this exact reason.
Being empathetic doesn't imply also being compassionate. Maybe we vie for power so much exactly because we do have a deep awareness of other people's feelings and people who wield power can say, "If I'm not happy, nobody is happy." All this conflict comes from not having to depend on people in power for our happiness.
