The cosmos is a single living being, pervaded by a single pneuma and a single Logos. All its parts are bound by sympathy (συμπάθεια): a movement in one resonates through all. Rational beings share in this unity at the highest level — through their common intellect (TERMnous), which is a TERMportion of the cosmic Logos. Every separation, therefore — between human and human, between human and nature — is illusory: each is a part (μέρος / μέλος, "member" or "limb") of a single body.

SVF II 473, 528, 532, 546 (the doctrine of συμπάθεια and of the pneumatic continuum); 1027 (the cosmos as a living being); DL VII 138–143; LS 47, 54. In Marcus the doctrine recurs as a leitmotif: Med. 4.40; 6.38; 7.9 ("all things are interwoven, and the bond is sacred"); 9.1; 9.9; 12.30.

In 02-01 this doctrine is the load-bearing ontology of the argument: if all human beings are particles of a single Logos, then mutual counter-action is the self-fission of the whole. The body-images (body-parts, cooperation) are the anthropomorphic expression of cosmic unity: rows of teeth, eyelids, and hands cooperate because they are one body — and so do human beings, because they share one Logos. See oikeiosis (the ethical correlate) and view-from-above (the exercise that makes the unity intuitively evident).