Time is nature's way of keeping everything from happening at once ........ Howard Hoffman

Timing The Conscious and the Unconscious: Some Implications for Thinking ... and Thinking About Time Paul Grobstein 18 March 2003

The Place of the US in the World Community

BACKGROUND From Cheryl Chen conventional vs block model of time issue of free will? From Tony Rothman directionality of time simultaneity/causality From Peter Brodfuehrer all cells have materially-based cyclic rhythms time as change? unconscious time as basis of "prediction", in absence of "awareness" (consciousness, "intentionality"?)

A NEEDED PRELIMINARY:
NOTICING A CONSCIOUS/UNCONSCIOUS DISTINCTION IN BRAIN FUNCTION

(http://serendipstudio.org/bb/blindspot1.html)

(http://serendipstudio.org/bb/freewill1.html)

RECOGNIZING A CONSCIOUS/UNCONSCIOUS DISTINCTION
IN THE BRAIN'S HANDLING OF TIME

The issue of time resolution

Two sounds need to be separated by > 40 msec to be correctly reportable in terms of sequence
(cf http://www.nencki.gov.pl/PDF/AN/VOL62/kanab.pdf)

BUT nervous system makes/uses much finer time distinctions

• Pitch discrimination is about 2 Hz at 1000 hz ... a two millisecond time distinction
• Dichotic sound localization
  (cf http://eamusic.dartmouth.edu/~book/MATCpages/chap.5/5.3.local_spac.html) sound velocity 345 m/sec, head 0.25 meters
  sound goes one meter in 1/345 seconds = 3 msec
  1/4 of that across head = .7 msec

Another way to see the conscious/unconscious time distinction
(cited in B. Libet, Philosophy of Science 48: 182-97 (1981), according to Norretranders, p 225 and note) Simple reaction time is 200-300 msecs, and jumps to much longer times if one tries to slightly increase them. Conscious processes are slower than unconscious ones.

SIMULTANEITY (AND HENCE CAUSALITY) AS A GENERAL PROBLEM
GIVEN THAT THE BRAIN IS A MATERIAL SYSTEM

Different time delays along different pathways
(cf Daniel Dennett, Consciousness Explained, 1991)

BEGINNING TO PUT THINGS (BACK) TOGETHER

Backdating by the unconscious, unknown to consciousness
(cf Tor Norretranders, The User Illusion, 1998, pp 213-251
Benjamin Libet, Neurophysiology of Consciousness, 1993)

Conscious sensation requires ~ 500 msec of cortical or thalamic activity
Stimulation of hand as much as 300 msec AFTER onset of cortical stimulation is reported as preceding sensation due to cortical stimulation
Therefore there must be a "time stamp" added in subcortical circuitry so conscious percept is backdated
Can verify using thalamic stimulation and verbal report ... occurence of sensation dated to beginning of cortical evoked potential rather than 500 msec later

BACKDATING (AND HENCE BIDRECTIONAL CAUSALITY) IS COMMON IN CONSCIOUS TIME ON MULTIPLE TIME SCALES

• Why withdraw finger when hit with hammer? NOT because it hurt, that came later
• Intepretation of language - meaning of words at beginning of sentence frequently depend on words much later
• Psychoanalysis (and other forms of "learning about oneself")

TIME AS SEQUENCE (and CAUSALITY?) IS CHARACTERISTIC OF CONSCIOUS PROCESSING ("EXPERIENCE", STORY-TELLING),
BUT NOT OF NERVOUS SYSTEM AS A WHOLE
NOR OF ITS PRIMARY INTERACTIONS WITH "REALITY"

• Damasio's patients: can recall events but not times
• Memento: need to consciously reconstruct story
• Is it perhaps the processes underlying "consciousness" - the abilityto backdate - which give rise to "block model" of time?
• Does not in fact follow that past (or future) exist outside the story
• What DOES "time" look like/mean unconsciously? Continuous unstable present?

RELEVANCE TO FREE WILL?

• Permissive argument: block model may NOT hold for "reality"
• Unconscious has unpredictability/indeterminacy
• Conscious CAN act to influence behavior, given enough time

  

• Can even act to influence "willed" behavior given enough time (Libet)

Some additional useful links on-line

Daniel Dennett and Marcel Kinsbourne (1992) Time and the Observer, Behavioral and Brain Sciences 15: 183-247

Time, from The Internet Encylopedia of Philosophy

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