This brief and simplified discernment is to further elaborate on https://www.epistemologyontologyfoundationinstitute.org/philosophy-and-science/on-philosophy-and-science-of-perception-and-living-experience:
1.0 The heart is not only the first organ, but also the 1st intelligent organ (i.e. has much neurons). And as well as the strongest spectra-field. And therefore, also the most subtle and sensible.
2.0 From 1.0, the heart facilitates whole form-formless or many sentient composite body-mind system to emerge.
3.0 From 1.0-2.0, the heart is the 1st organ that is intertwined and entangled with and in the local and non-local cosmos.
4.0 From 1.0-3.0, sustain form-formless or many sentient composite body-mind system through life cycle which facilitates the emergence of wholeness consciousness and awareness or subtle body-mind.
5.0 And is also the organ that end life in the known physical world other than due to causes of diseases or illnesses in other body parts. Even then, transition of spirit-soul potentialities of possibilities is still at the end of heart cycle or disentanglement of subtle body-mind from physical body. And which complement nature process as briefly simplified in 1.0-4.0.
And therefore, the heart has the most subtle link to the subtle body-mind of the many sentient composite body-mind. When ancient traditions refer to breathing or practice breathing, there are multiple meanings or practices:
1.0 Breathing to better or maintain health (i.e. cardiovascular).
2.0 Breathing to maintain body rhythm or synchronization.
3.0 Breathing to resonate with the cosmos or the ground of being and nature. And this is referring to the heart in synchronization with the brain which related to 1.0-3.0 in previous paragraph.
5.0 All the above.
Certainly, many would argue that presently, the heart can be replaced or transplanted but not the brain. However, a mechanical heart is different than a natural heart. And even natural heart would required adaptation to the whole body-mind. One can also argue that people not only can be alive but also maintain a normal life with almost no brain or part of brain remove while this is not possible with the heart. However, these anomalities are beyond the intent in this discernment.
And which was why many traditions across the millenniums, the heart was considered as the most sacred. And portal mechanism potentialities of possibilities to the sacred or divine. And which was why heartful care is not only crucial but essential process of wholeness ways of life to complement or better process of mindful care ways of life.
Epistemology of Life and Ontology of Existence Foundation and Institute