Mechanism / Vitalism

The classical opposition in philosophy of biology between mechanism (the organism is reducible to its physico-chemical parts and processes) and vitalism (the organism is governed by an irreducible vital principle, entelechy, élan vital, etc.) defines the conceptual problem-space MP's philosophy of biology operates within. MP rejects both: he refuses mechanism's reduction of organic form to physico-chemical aggregation, and he refuses vitalism's positive principle (a "soul" or entelechy added to the physico-chemical). The third position MP develops — institutional teleology, articulated through the "operant whole" in Nature (1956–60) and through the "kinetic melody" / three-orders-of-signification register in Structure of Behavior (1942) — is neither mechanism nor vitalism nor the contemporary closure-based naturalist alternative (Maturana-Varela autopoiesis; Mossio-Bich, Weber-Varela organizational closure). Per Halák's reading in M-C 2026 Ch 5, MP's institutional teleology is structurally incompatible with the closure-based alternative as well — making the "third position" reading a corrective on the contemporary naturalization-of-teleology debate.

Key Points

MP's rejection of both classical poles. Nature 155: MP "consistently warns against two symmetrical errors: 'placing a positive principle (idea, essence, entelechy) behind phenomena, and not seeing any regulative principle at all'." Vitalism's positive principle and mechanism's no-principle are both misplacements; the third position rejects both moves.
The "operant whole" / "certain dimension". Nature 155–156: "The whole demonstrates an 'efficacy' and is 'operant' within the organism, not as a governing principle, but as 'a certain dimension'... whose openness makes it possible for the organism to reorganize itself." A gap always persists between the organism's factual configuration and its totality — what MP calls the "natura naturans" register.
The retrospective-illusion warning. Nature 152: to "read in the [axolotl's] first movement the act of swimming" and to "project what is yet to come into the past" is a "retrospective illusion." Teleology cannot be naturalized by projection of a future state into the genesis. "Living nature is not simply the position of something [specific]... It is the primordial establishment of the problematic [un premier avènement du problématique]."
Closure-based naturalism is a third pole MP also rejects. Halák Ch 5 §5 (M-C 2026 lines 2455–2467) directly contests Thompson's autopoietic reading of MP's Structure of Behavior and reads MP's Nature lectures as anti-autopoietic. Halák's fn 127 cites Beith pp. 38–41 as corroborating. The recent organizational-approaches literature (Di Paolo, Montévil et al.) recognizes variability, historicity, contextuality — but still preserves closure to keep the teleology-naturalization claim. MP's institutional account doesn't.
What MP's account explains that closure cannot. MP's institutional teleology explains useless formations, expressive bodies (Portmann), and human culture — phenomena closure-based naturalism cannot account for. (Halák concedes this argument is "gestured at rather than developed" within the chapter.)

Connections

is the problem-space of MP's philosophy of biology — the mechanism / vitalism opposition is the historical conceptual frame MP's SB, Nature, and Phenomenology all situate themselves against.
is rejected by institutional teleology — MP's institutional account is the third position; see organismal-institution for Halák's coinage.
contrasts with experimental Platonism (Ruyer) — Ruyer's finalisme offers another non-mechanism / non-vitalism alternative; MP draws on Ruyer selectively.
contrasts with contemporary closure-based naturalism (autopoiesis, organizational closure) — Halák reads MP as incompatible with this third pole as well; this is the corrective register of MP's reading.
connects to multilateral-emergence (DD 2024) — non-teleological emergence as a related anti-naturalization register.
connects to three-orders-of-signification — SB Ch III's distinction (matter / life / mind) is part of MP's developing alternative to mechanism / vitalism in 1942.

Open Questions

Thompson's Mind in Life (2007) not in raw/. The cardinal contemporary autopoietic reading of MP that Halák contests is not directly available on the wiki. The contestation runs through Halák's mediation only.
The internal vs external scope of the non-naturalizability claim. A reader could accept the MP-internal claim (MP's institutional teleology is incompatible with closure) and reject the external claim (closure is the right account; MP is wrong). The external naturalization debate is left open by claims#mp-teleology-non-naturalizable (live).
Ruyer 1958 La genèse des formes vivantes not yet ingested. Ruyer's mature formulation of biological finalisme is one of the alternative non-mechanism / non-vitalism positions MP draws on; the relation has not been audited.
Whether the "third position" framing collapses into a single position over MP's career. SB (1942)'s three-orders register, PhP (1945)'s body-schema register, Nature (1956–60)'s "operant whole" register — are these one continuous third position, or three distinct attempts? Per claims#mp-1942-already-prefigures-late-sedimentation and claims#sb-1942-kinetic-melody-origin, there is at least continuity from 1942 to the late ontology; the question of unity is open.

Synthetic Claims

live claim, see claims#mp-teleology-non-naturalizable — MP's institutional account of organismal totality is structurally incompatible with autopoiesis (Maturana-Varela) and organizational-closure accounts (Mossio-Bich, Weber-Varela) of teleology. Organismal teleology — on MP's reading — is not naturalizable. This page is named wiki home for the corrective register: the wiki tracks mechanism / vitalism as a problem-space MP traverses by rejecting both poles and the contemporary closure-based "third pole."
live claim, see claims#anticipation-retroaction-as-temporal-signature-of-life — per Halák (M-C 2026 Ch 5 §4.1), the temporal structure "anticipations and retroactive integrations" is the distinctive temporal signature of organic life on MP's account, structurally parallel to MP's chiasm but operating in ontogenetic time rather than perceptual or ontological time. Bears on this page because the third-position commitment (rejecting both mechanism and vitalism) is operationalized by the anticipation-retroaction temporal structure: what makes MP's institutional teleology distinct from autopoietic closure is precisely that the organism's totality is "operant as a dimension" — anticipation-retroaction is the diachronic mechanism that maintains openness against both reductive-mechanistic and substantivist-vitalist closures. Coordinates with mp-teleology-non-naturalizable (live): the anticipation-retroaction temporal-signature is the operative form of the non-naturalizable institutional teleology.

Sources

mendoza-canales-2026-institution-ontology-politics — Halák, Ch 5 §5 (pp. 137–139, lines 2417–2467). The non-naturalizable framing; direct contrast with Mossio-Bich, Weber-Varela; contestation of Thompson's Mind in Life.
merleau-ponty-2003-nature — Nature 152, 155–157. The retrospective-illusion warning; the "operant whole" / "certain dimension" formulations; the symmetric-errors warning against vitalism's positive principle and mechanism's no-principle.
merleau-ponty-1942-structure-of-behavior — the three-orders-of-signification register and the kinetic-melody origin: 1942 already prefigures the third-position commitment.
beith-2018-birth-of-sense — Beith pp. 38–41 (cited at Halák fn 127). Beith's tripartite passivity reading converges with Halák's institutional reading on the rejection of autopoietic closure.