Response to a questioner:Whether you believe that there are free starting-points or not has everything to do with your commitment to two alternative conceptions of time itself. For modern science, i.e. scientific method, time is cast as continuous, one-dimensional, linear, which amounts to a commitment to the absoluteness of efficient causality that generates all movement/change, proceeding moment by moment, from the past to the present moment into the future that accordingly arrives deterministically. For this view, which amounts to modern science's founding superstition, there is only a block universe in which there can be no free starting-points and in which time is an illusion that can cleverly be eliminated from the physical equations of movement of all kinds. Without linear, one-dimensional time with its corresponding efficient causality, modern science collapses in favour of another vista in which the play of three-dimensional time comes into view.
If you return to your everyday phenomenal experience of living, which itself is a kind of movement/change, you can conceive of, i.e. presence in your mind, what might have happened back then, and also what might occur, presencing from the future. This presencing in the mind of what might have been and what might occur is already an indication that time is not a one-dimensional, continuous line connected by totalized effective causality, but is itself an openness open to possibilities that may or may not arrive within it.
Although, starting with your birth, you are cast into situations over which you have no control whatsoever, you nevertheless have the possibility of conceiving ('minding') and casting yourself one way or another into the future, whether this be on the small scale of your next everyday action or, in a wider casting, shaping your future life, indeed who you will become in casting your self. This is the abyssal nothingness of your self as a free starting-point (_archae_), a power as an origin of life-movement. You engage willy-nilly (nolens volens) with others, each of whom, in turn, is likewise a free starting-point and hence also an abyssal source of life-movement, i.e. an individual free power. This power interplay has its own compulsions and 'hard places' that will even negate your own intended aims, pushing you in one direction or another. The ongoing outcome of the power play among free starting-points is uncertain, incalculable, and is so only within the free, non-linear, three-dimensional play of the openness of time itself that provides the clearing for this interplay of individual powers. There are more degrees of freedom than modern science will concede, for it is committed to control over movements of all kinds, for the sake of setting-up all that occurs.
That, in any case, is how I see our sharing of the time-clearing with one another for as long as each of us participates in it, i.e. is alive, self-moving, self-changing.
Further reading: Being Time Space.