Think and feel what happens when you think. You get stimulus, you assess it, then when it rings true you get the feeling not in your head but your heart. Your conscience is the same source, the heart. Your sense of beauty when evaluating something, same place - the heart.

Christians would say it is the Holy Spirit that speaks to the heart.

Recent studies have indicated that there are neurons in the heart and the heart is more closely tied to the emotional brain than the cerebral cortex is tied to the emotional brain.