reactivity - the state or power of being reactive or the degree to which a thing is reactive.

Empathy is often defined as the feelings and actions that come up in response to what some else shares, their feelings and situation. For example, you see a homeless person, some people define empathy as the sadness, anxiety, stress, anger, pity, sympathy, concern, etc. etc. that come up in you.

These reactions will come up, but empathy is maintaining and staying present with the person.. all this may come up in the background,

In the Empathy Circle: While we are listening we just met the speaker with empathic presence. The various reactions may be going on in us but we set them aside and don't let them take over the space. When it is our turn to speak, we can fully share them and they will be met with empathy by the listener.

Split awareness; we can be having a high degree of presence with the speaker. There are a lot of other feelings arising in awareness as they speak, but the feelings and thoughts are let go, set aside, tabled, etc., for the time being.

Reaction is not Empathy.
Empathy is often defined as the emotional reaction the person has when they listen to someone .

Example, empathic distress. In this situation, someone sees (empathizes, feels into) someone else who is in pain or distress and they become distressed themselves. This is a reaction. This does not make sense or is not consistent to call this reaction empathy, since every reaction then should be called, empathic.

For example. one person has the reaction of joy arise when they empathize with someone, then that should be called Empathic Joy. To be consistent, there should be empathic sadness, empathic elation, empathic love, empathic anger, empathic empathy, etc., etc. So for me, reactions to empathizing with someone are not the core of empathy. Empathy would be the sensing into the moment to moment experiencing of the other. Even if these feelings arise in the listener in the background of their awareness.. The sense of empathy is still in the foreground of the listener.

Empathy Circle: how does this map over into the empathy circle?

Identifying: This also overlaps with identifying with the person. The homeless person is a veteran, and I'm a veteran, I have something in common with them. I start thinking of my experiences.