Da capo - from the head - from the beginning, a musical term directing "at the end of a piece of music to repeat from the beginning" (OED). Once again from the beginning.
But what is it supposed to mean with regard to the task of thinking? If it meant to go back to the beginning of Western thinking with the Greeks to simply repeat their 'piece of music', i.e. the historical trajectory of philosophical thinking to the present day, then this would get us nowhere. We would only end up back where we are today, our mind would not have changed. It must mean, instead, that in going back to the Greek beginnings, we are prepared and willing to change our mind, to recast our mind, by revising how the Greeks — notably Plato and Aristotle — answered questions regarding certain elementary phenomena on which our conceptions of all further, less elementary phenomena in the world depend.
What are these elementary phenomena? Apart from the question concerning human being or life itself (which are not the most elementary phenomena), Greek thinking struggled over centuries to conceive being and movement and hence also time. These conceptions have remained basic and determining for our Western (today globalized) mind to the present day. In Timaios Plato conceives being only as the opposite or negation of genesis, i.e. of becoming, movement. In his Physics, on the other hand, Aristotle conceives time as the number counted off movement, hence, as derivative of movement. This would render the phenomenon of movement as the central, fundamental phenomenon, because being is conceived as the unmoving, the unchanging (implicitly as enduring presence) and time as simply numerical, counted clock-time. Therefore the unchanging, i.e. being itself, is conceived as 'timeless', a thoughtless cliché still ubiquitously employed today!
But is time truly derivative of movement, or is it the other way round: Is it not rather the case that all movement and change, of whatever kind, can only happen in time? And that this time is more originary, more elementary than counted clock-time? Does not the striving to think as truly as possible to the phenomena themselves demand that we radically rethink time itself? Perhaps even that time is not a physical phenomenon at all, but pre-physical (and certainly not 'psychological' in the insipid modern sense of the term).
Since not all movement and change is physical — with physical beings, since they are extended, requiring space — there is also pre-spatial movement, e.g. the movement of the mind itself, focusing on this or that. This existential movement of the mind itself, however, presupposes the open, originary, three-dimensional time unifying present, past and future in which it can happen at all. Our mind belongs to time; all mental movement is temporal in this sense of focusing (in German: Vergegenwärtigen).
Hence time and space are phenomenally not on a par with each other at all; rather time is more elementary than space, that is, it is pre-spatial. With this observation, a well-entrenched and massively fortified dogma of all our (Western?) thinking falls to the ground. And yet the clichés of time and space as on a par with each other and of time as sequential clock-time, i.e. as consecutive 'nows', live on today unquestioned and unperturbed. As if we had forgotten what it means to think and remain content with modelling in flimsy, hypothetical, theoretical constructs that are then — too late — empirically tested.
Counted, linear clock-time went on to have a spectacular career on the historical trajectory of the cast of our Western mind. Galileo, Descartes and Newton mathematized it for the sake of gaining mastery over physical movement. Very clever and effective. Einstein spatialized this linear, counted time by conceiving it as the path of light tied to three-dimensional space as observed by a subject with its apparatuses, such as telescopes. Hence the Lorentz transformation in special relativity (straight light path) and the Riemann tensor (curved light path) in general relativity.
Attempts to fuse general relativity with quantum mechanics in quantum-gravity theory have prompted the striving to get rid of (the phenomenon of) time altogether (as an 'inner' psychological fiction) in the mathematical modelling of what is supposed to be 'the case'. But perhaps only certain, restricted kinds of movement can be conceived as happening in this 'skinny', mathematized, linear time — the time of linear causality that cannot cope with quantum indeterminacy, not with that sociating kind of movement I call interplay.
What if what is become of time is also intimately intertwined with what is become of us, of our mind, in Western history? In other words: What if how our Western mind conceives time is intimately intertwined with who we conceive ourselves to 'be' in belonging to the openness of time? What if rethinking time necessitates our rethinking the entire temporal structure of the world with its various kinds of movement?
What I have written here is only a tiny indication, a teeny-weeny tit-bit of the enticing challenge confronting us today: to rethink da capo. Not for the faint-hearted, and also an immense, multi-generational task with a myriad facets, but also necessary if we are ever to learn to stop simply mouthing clichés of thought in outworn language that serves to perpetuate the status quo with its seemingly endless techno-scientific progress. Such as the latest, inevitable innovation: algorithmic control of all kinds of movement through AI. It's been a long time coming since Plato broke down the logos into discrete bits.
Further reading: On Human Temporality.