well join the club
that's the one we are all talking about and while I may have physically joined the conversation late, I have definitely been here in spirit as a lurker
jokes aside, the heart is used figuratively.
“And Jesus, knowing their thoughts, said, Why are you thinking evil things in your hearts?” Matt. 9:4
there are other scriptures indicating conscience, purpose etc
the word 'heart' is used for all of them. even so, you cannot purpose to do something without the use of your mind
your conscience is not a physical, tangible thing
your will is determination
none of these things indicates a mystical heart