In fact I thought myself an empath in the past. Though its hard to prove, the symptoms all pointed to it. There are many senses that we do not fully understand, specially the functions of our brains. It has been theorized that we absorb a lot of information subliminally, whether it is from facial expressions, tone of voice, word choices or even something small as a delay between words. We cannot actively figure out what is going on in a persons head with this information alone unless we have specific psychological and human behavioral training. Our brains on the other hand, exhibit these features when under the same types of stress, therefor it knows how to recognize it, even if we don't.