Empathy and sympathy are closely related words and concepts, but each is quite distinct from the other.
Both words draw part of their meaning from the Greek word pathos which means feeling and came from the PIE root *kwent(h) which means to suffer.
Empathy is an early 20th century word with much older roots.
To have empathy (n) is to empathise (v): to share a feeling, or more literally to be in the feeling, that someone else experiences. It suggests an ability to fully understand how another person feels and how their experience affects them both emotionally and practically. A person who empathises readily or easily is described as empathetic (adj) because they respond empathetically (adv).
Empathy is what Atticus Finch was teaching his daughter in To Kill A Mockingbird:
“First of all, if you learn a simple trick, Scout, you’ll get along a lot better with all kinds of folks. You never really understand a person until you consider things from his point of view . . . until you climb into his skin and walk around in it.”To Kill A Mockingbird, Harper Lee
In other words, empathy is necessary for understanding other people, and therefore their experiences and behaviour, too.
Sympathy differs in that it relates to sharing a feeling or experience with or alongside someone else. It has a sense of commonality and community, where empathy is more individual. One who sympathises (v) is described as sympathetic (adj) because they respond sympathetically (adv).
Sympathy is a much older word, dating back to the 1500s, when it entered English via French ‘sympathie’ from Latin sympathi‘ and before that, from Greek sympathes which meant to have a common feeling or to be affected by similar feelings. The prefix sym- means together so when added to pathos, the meaning is feeling together – synonymous with compassion, which literally means suffering together.
The differences are subtle, but definite. Consider these example responses to a person grieving a loved one:
Empathy: ‘I understand that you are sad and hurting. I understand life will never be the same again. I’m here for you.”
Sympathy: “I share your sorrow and pain. Life will never be the same, but I am here with you.”
In both cases, the person understands they are not alone, but the ways in which their experience is understood and shared differ.
Crucially, both empathy and sympathy must be genuine in order to actually exist. Token words and empty expressions are meaningless.
If one is unable to connect at any level with the experiences of others, or to offer anything other than a token acknowledgment of someone else’s suffering, they have neither. There are such things as empathy training and empathy coaches, but if the subject does not have the capacity for it, one may as well try to teach a fish to walk.
Etymonline: Empathy and Sympathy