McKemmish Laura K, Reimers Jeffrey R, McKenzie Ross H, Mark Alan E, Hush Noel S
School of Chemistry, The University of Sydney, New South Wales 2006, Australia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Aug;80(2 Pt 1):021912. doi: 10.1103/PhysRevE.80.021912. Epub 2009 Aug 13.
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.
彭罗斯和哈梅罗夫认为，仅基于神经网络的传统脑功能模型无法解释人类意识，他们声称还需要量子计算元素。具体而言，在他们的协同客观约化（Orch OR）模型[R. 彭罗斯和S. R. 哈梅罗夫，《意识研究杂志》2，99（1995）]中，假定微管充当量子处理单元，单个微管蛋白二聚体构成计算元素。该模型要求微管蛋白能够以相干方式在不同构象状态之间切换，并且这个过程在生理时间尺度上要迅速。在此，根据最近关于微管组装和动力学的实验研究，对Orch OR提议的生物学可行性进行了检验。结果表明，微管蛋白并不具备Orch OR提议最初所提出的成立所需的基本特性。此外，我们还考虑了对生物系统中长寿命相干运动（这对Orch OR至关重要）理解的最新进展，并表明基于已知物理范式对该提议进行的任何改进都无法在微管内实现量子计算。因此，Orch OR模型不是意识起源的可行解释。
