Defending Orch OR against critical attack from Australian A.I.-funded group
On YouTube
The following is my abstract for poster presentation at the upcoming Toward a Science of Consciousness.
I will write a full reply in the future.
Stuart Hameroff
INTRODUCTION The Penrose-Hameroff orchestrated objective reduction (Orch OR)
theory postulates quantum computation in microtubules (MTs) inside brain
neurons as an explanation for consciousness. Orch OR has been attacked by
McKemmish et al (Phys Rev E, 80:021912, 2009) who assert Orch OR in MTs is
biologically unfeasible, and unsalvageable. BACKGROUND MTs are cylindrical
lattices of peanut-shaped tubulin proteins. The basic Orch OR idea is that
discrete MT tubulin states act as information bits and quantum bits (qubits) in
MT computers inside brain neurons. Orch OR suggests MT tubulin qubits switch
coherently and compute by entanglement with other tubulins, performing quantum
computations which self-collapse by Penrose objective reduction.
SPECIFIC CRITICISM OF ORCH OR McKemmish et al focus on switching between
discrete tubulin bit and qubit states, describing tubulins flexing between two
conformations (shortening by ~3%) depending on GTP hydrolysis to GDP. They
assert such GTP-dependent switching is involved in MT ?treadmilling? in
which MTs polymerize at one end and depolymerize at the other, finding such
conformational switching too slow for Orch OR.
RESPONSES IN DEFENSE OF ORCH OR
1) Neuronal MTs have specific caps (e.g. STOP proteins) which stabilize MTs, preventing
depolymerization and treadmilling (J Cell Biology 142:167, 1998). Hence the McKemmish et al
scenario does not generally apply to MTs in brain neurons.
2) Contrary to McKemmish et al assertions, tubulin switching
in Orch OR is driven by quantum electronic London forces in hydrophobic pockets,
non-polar regions formed by aromatic amino acid rings and other non-polar
groups within proteins, and sites of anesthetic gas binding and action. Each
tubulin has over twenty hydrophobic pockets, including phosphorylation sites
for GTP, MAPs and CaMKII. Thus GTP hydrolysis is but one factor regulating
tubulin states and coherence, all potentially mediated through collective
London forces in quantum hydrophobic pockets.
3) McKemmish et al assume that protein conformation stems exclusively from atomic nuclear
motions which then affect delocalizable electrons. This is the bus turning the steering wheel. The
rationale for quantum devices is for low energy quantum states to be amplified
to regulate conformational (nuclear) motions. Thus quantum events (including
conscious events) can exert causal efficacy in the classical world. McKemmish
et al completely miss the point.
4) Experimental evidence shows coherent dipole excitations in MTs at 8.085 megahertz
(Pokorny, Bioelectrochemistry, 63:321, 2004). McKemmish et al validate MT megahertz
coherence, but claim it cannot help Orch OR because energy required to drive coherence of tubulin
conformational flexion states is too high. But Orch OR requires superposition
separation of only diameters of atomic nuclei, and asserts low energy
electronic quantum London forces govern tubulin states. Megahertz coherence in
MTs strongly supports Orch OR.
5) McKemmish et al assertions that Orch OR is
untenable and unsalvageable are based on misrepresentations and misconceptions.
Their funding (from Artificial Intelligence) and statements such that "denial of
Orch OR gives hope to the vision that digital computing could achieve truly
significant levels of artificial intelligence" shows their attack is not science
but a political hit job.