Penrose-Hameroff orchestrated objective-reduction proposal for human consciousness is not biologically feasible.
Laura K McKemmish, Jeffrey R Reimers, Ross H McKenzie, Alan E Mark, Noel S Hush
Physical review. E, Statistical, nonlinear, and soft matter physics August 1, 2009 DOI: 10.1103/physreve.80.021912 (opens in new tab) via PubMed
Summary
AI-generated from the abstractThe Orch OR model, which proposes that microtubules in brain cells perform quantum computations to produce consciousness, is not biologically feasible. Recent experimental studies on microtubule assembly and dynamics show that tubulin proteins lack essential properties required for the model to work. Additionally, progress in understanding long-lived coherent motions in biological systems demonstrates that no reformulation of the proposal based on known physical paradigms could enable quantum computing within microtubules. Therefore, the Orch OR model is not a viable explanation for the origin of consciousness.
Study at a glance
| Characteristics | Theoretical or philosophical paper Peer reviewed |
|---|---|
| Key finding | Argues that the Orch OR model is not a feasible explanation of the origin of consciousness because tubulins lack required properties and no known physical paradigms could enable quantum computing within microtubules. |
Abstract
Penrose and Hameroff have argued that the conventional models of a brain function based on neural networks alone cannot account for human consciousness, claiming that quantum-computation elements are also required. Specifically, in their Orchestrated Objective Reduction (Orch OR) model [R. Penrose and S. R. Hameroff, J. Conscious. Stud. 2, 99 (1995)], it is postulated that microtubules act as quantum processing units, with individual tubulin dimers forming the computational elements. This model requires that the tubulin is able to switch between alternative conformational states in a coherent manner, and that this process be rapid on the physiological time scale. Here, the biological feasibility of the Orch OR proposal is examined in light of recent experimental studies on microtubule assembly and dynamics. It is shown that the tubulins do not possess essential properties required for the Orch OR proposal, as originally proposed, to hold. Further, we consider also recent progress in the understanding of the long-lived coherent motions in biological systems, a feature critical to Orch OR, and show that no reformation of the proposal based on known physical paradigms could lead to quantum computing within microtubules. Hence, the Orch OR model is not a feasible explanation of the origin of consciousness.