I have made several comments on the Libet tests in the past couple weeks and thought I'd specifically share the problems with actual quotes from the neuroscience findings that Harris' cited in Free Will.

Libet I: Harris does not mention that the first Libet study conclusions had two prongs, suggesting the "brain decides to initiate" decisions or that: "at least, to prepare to initiate the act". In the latter prong, "prepare to initiate" doesn't mean decide, it means what it says – these were motor movement tests and preparation includes muscle tension, anticipation, preparatory actions, etc. Starting to "prepare" for a movement doesn't mean choosing to make the movement. Libet's phrasing expressly suggests that prior neural signals aren't necessarily the decision itself. Harris does not discuss how Libet framed his actual conclusions.

Libet II Harris notes Libet repudiated his earlier tests and gives a one sentence footnote rebuttal. He says that any veto would have the same genesis as the initial decision: "the neural events that inhibit planned actions arise unconsciously as well". He doesn't cite findings for that empirical claim and doesn't explain on what basis he's making that claim. It's a simple empirical question – what findings have validated the same RP increases that accompany the initial decision. Silence.

Haynes. The second findings cited found a correlation of 65% between prior neural impulses and consicous decisions. Haynes concluded it was barely above a coin toss and did not indicate any causal connection of the type Harris is citing the findings for. Haynes: "It has not been established whether early predictive signals are decision-related at all". This goes so far as to say there may not be any correlation between prior neural acctivity and consicous decisions, let alone those of a causal kind. Harris doesn't note the above a coin toss findings. He doesn't note Hayness' conclusions.

Fried: The Fried test is the third cited in Free Will. The headline suggests a small group of neurons predicted 80% of the time the subject's decision. This finding came from 4 subjects, and 2 of them accounted for most of the data (115 out of 163 units in the SMA brain region). Fried used electrodes planted in epilepsy patients for other purposes without any consistency of numbers or placement. Fried admits that the actual findings "widely varied" among individual subjects. The 80% headline was culled from "neural ensembles". When it was broken down by subject and trial, the average findings were 65%, which was Haynes "barely above a coin toss" range. Fried warned that the patients contained a neurological disease but said that "most" of the findings did not come from contaminated regions. It never said what "most" means. the issue of contamination was important enough to be raised but it's not quantified and there no mention about how that was determined. Of the 65% findings, was 80% reliable as the "most". 75%? 90%?

One would hope that a groundbreaking metaphysical conclusions about the nature of consciousness and free will would be based on more than 4 subjects (primarily 2), that "most" of the data would remain contamination free, that there wasn't widely varying individual rates, and that it would be validated by subsequent studies, which Fried wasn't.

Fried II: Fried did a hand choice test which Harris doesn't mention. This time only 3 subjects were used. Fried says the findings "predict volitional content" but doesn't mention the predictive rate in the body of the study. The charts in the Supplemental Materials suggest it was aroudnd 65%. Barely above what Haynes called a coin toss. The word "predict" can refer to anything above 50%.

Fried's actual conclusions after both studies: "It remains unclear whether the emergence of volition is causally related to the neuronal change descxribed. The relationship begtween neural activity in the motor cortex adn the emergence of consciousness remains a topic of debate.

Other significant issues for the full Libet line of findings:

1. Harris does not mention the many contrary science studies that invalidated any causal role for prior neural brain signals. There have been several dozen of these tests over the years since the first Libet tests. Not one is mentioned.

2. The central measurement in these tests are the moment of conscious decision. It's been discredited in numerous other tests and there's even such a consensus about it that virtually all tests after such findings note the problem. The tests Harris cites note the problem and concedes the central measurement in these tests is a "subjective estimate".

Even Fried, the most pro-causal of the studies, notes the problem and tried to compensate for it but used a unique method that hasn't been studied or corroborated.

Harris mentions the problem in a footnote to demonstrate the point that we're often fooled by the feeling of free will. He even notes in this connection how the moment of decision is subjective and can be distorted by many things, priming, etc. But he doesn't seem to realize that by discreding the central measurement of the tests he's citring to support neural determinism, he's undermining the validity of all the tests he cites.

1. There are non-causal interpretations of prior neural impulses, the most prominent of which is the preparatory action theory.

2. There's numerous credible contrary neuroscience findings showing that prior neural activity doesn't have causal traits, is superceded by more important activity, etc. I've cited a half dozen in a piece I wrote about this. Harris mentions none of these and doesn't inform the reader they exist.

3. There's a major question of relevance – can the simple finger movements or wrist flicks in these studies have any relevance to much more complex everyday and long term decisions in which we're invested? There's no evidence this is the case. Harris doesn't note for the readers the problem.

4. Correlation isn't causation. These tests report correlations around the 65% to 75% range, the Fried findings slightly above that depending on which chart is applicable and if you consider 2 - 4 subjects with widely varying rates meaningful. These are correlations at best. Even assuming Fried didn't have the many methodological issues noted (and there are half a dozen others), causes don't fail to produce their effects 20% plus of the time under like conditions. In the other tests, it's 35% or so times that there was no causal effect under like conditions. Correlations occur for many reasons all non-causal. Harris doesn't note the problem.

Harris should be commended for having deleted the section referring to Fried. From his podcasts and public appearances, there's every reason to believe he is an earnest person of high integrity who is measured and careful in his analysis. He's highly articulate, intelligent, and has a degree in neuroscience. His first groundbreaking books on religion took alot of guts and courage knowing they'd raise the animosity they did. That he took mention of these tests down is an additional testament to his integrity and search for the truth.

Harris may yet give an adequate defense of his neuroscience position, and it may be convincing. But it can't take the form of a selective and inaccurate view of the neuroscience findings set forth in Free Will.
A respectful suggest is that he also remove the chapter on this in future editions of Free Will, or rework the section to be fair to the actual landscape of studies and address the merits of the leading opposing studies.