Transformation, change of state. For the Stoics, μεταβολή is the fundamental process of the cosmos's existence: fire becomes air, air water, water earth — and back again (the so-called κυκλικὴ μεταβολή, the cyclical transformation of the TERMelements). Every particular thing is only a temporary configuration in this flow: birth is the transformation of matter into a compound body (συγκρίμα), death is the transformation of the compound back into the elements. Death is therefore not an ontological "loss": nothing disappears, everything passes over.

SVF II 413–425 (transformations of the elements); II 596–632 (the role of pneuma in transformations); II 596 (the doctrine of the cycle, κύκλος); DL VII 142; LS 47, 52. The Heraclitean background (to which Marcus himself appeals): Heracl. fr. 30, 36, 76 DK. In Marcus μεταβολή is a leitmotif: Med. 2.3; 2.17; 4.3.8 ("the substance of the universe is a river"); 04-36 ("everything that exists is the seed of what will come to be from it"); 04-42 (change is neither evil nor good); 05-13 (the parts of the self into parts of the cosmos, endless transformation); 05-23 (substance a river in perpetual flow, activities in ceaseless μεταβολαί); 06-04 (all things τάχιστα μεταβαλεῖ — exhaled into the one or scattered apart); 6.15; 07-18 (nothing comes to be without μεταβολή; your own change is of one kind with the firewood's and the food's); 07-25 (nature will presently μεταβαλεῖ all things — that the world may be ever young); 07-47 (to contemplate the mutual μεταβολαί of the στοιχεῖα — it cleanses the grime of the life below); 07-49 (the μεταβολαί of dominions; the future of the same form); 09-01 (providence marked off the generative powers of μεταβολαί and successions); 09-19 (Πάντα ἐν μεταβολῇ — you too, and the whole cosmos, in ceaseless alteration and, in part, destruction); 09-21 (every change of age is a "death"; the μεταβολή of one's whole life is no more to be feared than the earlier ones); 09-28 (the ἐγκύκλια of the cosmos; the "surging waves" (ἐπικυματώσεις) of transformations and their speed — despise all that is mortal); 09-32 (the ταχεῖα μεταβολή of each thing — against it what troubles you is nothing); 09-35 (ἀποβολή = μεταβολή: loss is only change, and nature delights in it); 09-36 (the breath of life too is "another such thing", μεταβάλλον from this into that); 12.21.

In 02-03 μεταβολή executes the final argumentative turn: "the cosmos is preserved both by the changes of the elements and by the changes of compound bodies." My individual death, that is, is not a contradiction to the cosmos but its mode of continuation. This thought is the principal Stoic answer to the fear of death: what we fear is the very process that produced us. See meditatio-mortis (the exercise) and the doctrine amor-fati (acceptance of what happens).