It is interesting to me that the new year could start in any season of the year but most start at the end of winter or the beginning of spring (half full or half empty). Those cultures or countries that do not seem to be either 1) near the equator, 2) in the Southern Hemisphere or 3) are countries of former European colonial powers.
The choice of when to start seems therefore to be informed by the life cycle – birth, sickness, old age and death.
It would be ironic (and slightly humorous) to start the (re)cycle half way through the circle of life. We perceive life with a start middle and end, not a middle, end and start (or the other combination). That is just “natural”.
All things are the basis of our decisions. We are embodied. We are exist firstly as body, only then do we have a mental/spiritual/conscious “life”.
There are truly many ways to look at the relationship between body and mind. Starting with Plato and Aristotle, through to Descartes, Spinoza and Leibniz, we have various formulations (conceptualisations) to explain or understand this relationship. We are, I believe, continually (recurringly) searching for an understanding.