Wednesday, September 30, 2009

Distinguishing between apparent and real time in reporting Libet-related research

Here's a distinction that many writers seem insufficiently sensitive to in reporting research by and about Libet and the questioned efficacy of conscious will: It's the distinction between when something seems to have happened and when something really happened. This is a distinction we might label as that between subjective and objective time or apparent and real time.

It seems easy enough to acknowledge such a distinction and find clear cases of its applicability. Unbeknownst to George, his watch is 5-mins fast. So, when some event actually happened may be a quite different time (a difference of 5 mins) than when it seemed to George to have happened. This is so simple, that young children can keep them apart. So whence the alleged difficulty?

Things start to get a bit confusing when we realize that mental events we can call seemings can have real objective times of occurrence too. Especially confusing is when the seemings concern times of occurrence. Ordinary language is ill-equipped to keep the real time/apparent time distinction clear in describing such situations. (My spell-checker is hating on "seemings" right now.) Suppose George's seeming objectively occurred at 12:50, but it seemed to George that the mental event in question occurred at 12:55. Note how totally ambiguous a statement like the following can seem once such a distinction is in mind:

"It seemed to George that he made a conscious decision at 12:55 to flick his wrist"

Is 12:55 here the objective time of the seeming or the subjective time of occurrence according to George?

Here's some recent blogging on Libet that seems to me to make the mistake I'm talking about.

From "I didn’t do it, my brain did" @The Philosopher's Eye

In 1983 Libet showed that before subjects announced their decision to perform an action (and hence, or so Libet assumed, before deciding to perform an action) their motor cortex was already preparing the way for the act in question.

It seems that the safe thing to say of what Libet showed is that the apparent (according to the subject) time of the conscious descision was later than the objective time of the (perhaps conscious) decision.

From "
Libet was wrong...?" @Conscious Entitites

...Benjamin Libet’s remarkable experiments, which seemed to show that decisions to move were really made half a second before we were aware of having decided.

Here the crucial ambiguity is with "half a second before we were aware of having decided." Is that 1/2second subjective? If so, that's a modest, though unexciting, description of what Libet showed. Is it instead objective? That would be very exciting indeed, but it's a great mystery how Libet, or anyone, could possibly show such a thing.

Anyway, the line I'm recommending here is what I take to be be one of Dan Dennett's key insights in his various discussions of Libet, so I don't pretend any originality here.