While I use concepts like heart and mind to explain what happens in me, I think they are both the same reality. Each notion is simply a different aspect of what I think is my core essence. Perhaps my heart is like the vast, throbbing, energetic part of me, like water is the ocean. My mind and constant thoughts are the waves on the surface that give an apparent shape to the water below.
When I think of how my mind and heart relate to one another, I remember what it is like to stand on my cabin dock at night. When the night is cloudless, and there is no wind, the lake is without ripples. The surface is as smooth as glass and it reflects the sky above. The moon and stars are all reflected with clarity. When everything is still, the lake is a perfect and a clear reflection of the sky.
My heart is similar to my lake. When it is calm and the surface is smooth, I can see with clarity. When my mind is in repose, it is easier for my heart to be engaged with my world. All becomes clear.
For my heart to be engaged in this way, my mind must be free of disturbances and distractions. There can be no ripples. If there are ripples, then I see a fragmented image of reality. Things are not so clear.
Clarity comes when my mind is still. When my heart is relaxed, it sees and understands better and with more clarity than when it is rippled and disturbed.