Soul

We are all interconnected.  That connection is in the infinite.  The infinite is God and our part of that infinity is called our soul. All else is finite.
My brain is an anatomical structure. It’s an advanced animal model but insects have a rudimentary brain as well.  Some people have bird brains but they look human. Others are quite brainless but thanks to a soul they to are human.  Being human means having a soul.  Being homo sapiens means having a brain at least.  People with bigger and more efficient brains are smarter and more clever.
The mind can be best understood as the brain with soul. Wisdom is a coupling of the separate finite individual computer brain system with the infinite.  
The heart is an organ for pumping blood throughout the system.  The heart was once thought to be the seat of the soul. This is the ‘nous’.  We continue to refer to the ‘heart’ in the sense of the nous despite using the same term for a structural anatomic organ. Just as we vaguely associate the brain with wisdom so we associate matters of the heart with the heart.  It’s the ‘centre’ or in Eastern terms the chakra or energy centre associated with love.  People described being heart broken and loss of a loved one can cause death through heart attack or myocardial infarction.  The autonomic nervous system relates to the chakra system and to the acupuncture meridians.
It’s an intuitive centre and is associated in history with emotions.  The emotions today are understood however in the brain in the limbic system, i.e. the amygdala, hyppocampus, thalamus, cingulate gyrus etc. But even a child would more likely point to their chest when asked where love is, or where to you feel, rather than pointing to their brain.
The heart is mostly associated with love.  The love referred to when we speak of the heart is that of brotherly, sisterly love and agape, the highest love. Erotic love is thought a combination of heart love and the love of the loins or lust.  In eastern systems there is a lower chackra centre and acupuncture addresses loin issues in this region which coincides with another junctional area of the autonomic nervous system.
Oswald Chambers famous meditational book was called “My Utmost for His Highest”.  These were his ’soul’ thoughts.  Theology has had much to do about the rational ideas about God whereas religious ‘rituals’ and “practice’ have more to do with heart matters.   The best known 'practices' are prayer and meditation.  Scientifically they have been shown repeatedly as highly beneficial.
The soul is eternal.  When we die it’s thought that all that is organic dies, of course, but our soul goes on.  In computer terms this is considered as a program that will join a greater program intact like a usb stick memory drive or an ‘iCloud’ memory.  There is no reason to believe that we don’t continue.  It’s not essential to intelligence or advanced science to conceive of a non material core being of ourselves persisting with immortality.  Increasingly sciences sees the world as energy matrix and communication.  Religions collectively speak to this ‘after life’.  It is the soul, already a part of the immutable, a part of God, that persists.
With the soul goes love and wisdom.  Those who have near death experiences, and these have been post death of heart and ceasing of brain waves.  No one knows where the ‘self’ or ‘consciousness’ has gone but it comes back. These individuals report experiencing their whole life much like we would a memory card. What they were fearful about here was in that post death state somewhat silly because of the eternal all loving nature of existence as they now understood it.  So fear is temporal. Fear is finite while love is not.
This is why we say we are spiritual beings living in a material world. This is the perennial story. This is the central journey.