Heart is the centre or mine for circulation of blood.
The detailed description of heart is to be found in Anatomy. It
exists in breasts and lower animals and appertains to the material
world. We shall not refer to it in our book. The second meaning of
Qalb is soul with which we are concerned here. It is an
immaterial thing or formless Latifa or basic subtle element which
has got connection with the material heart. It is just like unseen
electricity. It is the principal thing in a man. It catches knowledge
of God and spiritual world..It is punished and rewarded. The
connection of soul with heart is the connection of attributes with
the bodily jlimbs, or a machine with the machine man, or a house
with its inmates. This connection is of two kinds. One kind of
connection is with Ulume Mokashafa or spiritual knowledge. But
in this look, our object is to narrate Ulume Muamalah or
knowledge of worldly usages. Its second connection requires the
knowledge of the secrets of soul. The Prophet did not throw light
on this object and so we should refrain from it. We shall translate
the word Qalb in this book as soul or an immaterial thing Latifa
with its attributes.