Re: Consciousness and Causality

From: HARNAD Stevan (
Date: Wed Jun 05 1996 - 18:35:15 BST

> From: "Carless, Rachel" <>
> Date: Sat, 25 May 1996 15:32:35 GMT
> When Libet was reaserching 'Conscious intentions',
> he wanted to try and discover exactly when a mental
> intention to carry out an act takes place. He believed that
> the only way this could be achieved was through an
> experiment which allowed subjects to self time themselves
> as they were the only ones who had access to their own
> experiences. The subjects were asked to look at a clock and
> told to flex their wrists whenever they felt like it whilst
> mentally making a note of the position on the clockface at
> the onset of the intention. Libet believed he was thus
> creating a recording of voluntary , internally generated
> actions.
> Libet found that motor potentials occured on average
> 550 ms before an action took place. He also discovered that
> the point at which the subjects recorded conscious
> intentions to move occured 200 ms before they did move.
> Therefore a difference of about 350 ms took place between
> the preparation to act and the conscious intention of
> acting.

So far, this is correct.

> On the basis of this evidence Libet advocates the
> idea of free will and us being accountable for our own
> actions.

No, this finding goes against free will; Libet tried to save free will
by suggesting that though our actions may not be caused by our wills,
but by unconscious brain causes, we can still VETO those actions with
our wills. (This is not convincing, because the most natural
extrapolation of his findings with actions is that the same thing would
happen with vetos: before we willed our vetos, are brains would already
have caused them.)

> This is because of conscious intentions occuring
> before movement, thus giving us time to allow us to
> consiously permit our own actions.

Please re-read the relevant parts of Libet, or Dennett's description of
Libet, because this last part does not convey understanding (and would
confuse kid-sib).

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