Ever since a 6 -year old video emerged of (then) Salk Institute intern James Holmes giving a 10 minute talk on "temporal illusions" - which can currently be viewed in toto at the website of the San Diego Union Tribune - the blogosphere has gone nuts with what this means. (Never mind Holmes' mentor at Salk, John Jacobson, told reporters that despite the presentation, Holmes' didn't appear to understand the basic science behind the work.)
Some bloggers have surmised the research meant that Holmes intended to "go back in time" and change the past so he could change the future or some such rot. Or, that he intended to alter his memory of what he intended to do in the future. When one watches the video one beholds Holmes waxing on about "subjective time" but in fact subjective time is a well known phenomenon not requiring peculiar neuro-science degrees, insights or computations. For example, G.J. Whittrow in his 'The Nature of Time' (Pelican Books, 1972, p. 103)gives a good account (with examples) of what is meant by "subjective time".
All it means is that the passage of interior time for a person, anchored in his particular consciousness, passes - or appears to pass - much more slowly depending on the event. If I am sitting in the dentist's chair and waiting for a crown to be fitted, this time will pass much more slowly, as compared to a delightful family occasion or party that appears to pass excessively fast. In more than one sense, then, subjective time is a psychological time for the person - but is not necessarily an "illusion", since by all accounts objective time (as recorded by the person's watch) still tells the true story. There is no contradiction or subversion of causality, in other words.
In a previous blog I cited Alex Rosenberg's book The Atheist's Guide to Reality and pointed out that perceptual systems are defective in the sense of being hindsight-biased: due to the finite speed of signal transmission, and delays due to neural processing, so changes in our immediate environments do not register in our experience instantaneously. Rosenberg bases all these on documented experiments, such as those by Lüder Deecke and Hans Helmut Kornhuber in 1964, showing that all human actions precede conscious decisions to perform them. For example, Rosenberg observes (p. 152) that: "On average it takes 200 milliseconds from conscious willing to wrist flexing and finger pressing".
Thus, to the ordinary (sensory deluded) human it appears as if he's willed and initiated the action, but he really hasn't. It's all an illusion. As Rosenberg goes on:
"But the cortical processes responsible for wrist flexing started 500 ms earlier. "
In other words, 500 ms before a test subject depressed a button to indicate when he felt the actual conscious act of willing was initiated. As Rosenberg concludes (ibid.):
"In other words, wrist flexing is already set in motion, and everything needed to complete it has already taken place 300 ms before the subjects are conscious of deciding to flex the wrist and press the button"
Rosenberg then goes on to argue the basis for "free will' is destroyed if the causality presumptively underlying it is a fiction. If the outcome has occurred before your actual intended action to effect it, there is no "free will" involved, the action was essentially done for you. Rosenberg then adopts this as a grounding for his notion that we are beings entirely governed by "blind sight". (I.e. p. 155, `Driving Through Life with Both Eyes Fixed on the Rearview Mirror').In other words, all our sensory outputs are based on ex post facto- conducted neural process corrections to much earlier sensory inputs that, for lack of a better term, need to be transduced.
The point is we aren't equipped to gain real time access to anything in our world.
The obvious implication? "Consciously deciding to do something is not the cause of doing it"
Cognitive scientist Daniel Dennett in his paper : "Temporal anomalies of consciousness: implications of the uncentered brain" provides a more technical cognitive analysis of how subjective time can be a victim of the sort of delayed neural processes discussed by Rosenberg and others. Dennett begins by focusing on “macroscopic time intervals” as he writes:
“This picture of how conscious experience must sit in the brain is a natural extrapolation of the familiar and undeniable fact that for macroscopic time intervals, we can indeed order events into the categories "not yet observed" and "already observed" by locating the observer and plotting the motions of the vehicles of information relative to that point. But when we try to extend this method to explain phenomena involving very short time intervals, we encounter a logical difficulty: If the "point" of view of the observer is spread over a rather large volume in the observer's brain, the observer's own subjective sense of sequence and simultaneity must be determined by something other than "order of arrival" since order of arrival is incompletely defined until we specify the relevant destination. If A beats B to one finish line but B beats A to another, which result fixes subjective sequence in consciousness? (cf. Minsky, 1986, p.61) Which point or points of "central availability" would "count" as a determiner of experienced order, and why? "
This, of course, is based on Dennett's model of consciousness explicated in his book, Consciousness Explained. in which he uses the concept of "multiple drafts". That is, a given conscious manifestation, of word or action, is the end product of editing and selection from amongst a raft of potential "drafts". Just as writers go through dozens of drafts before a final product emerges, so the individual consciousness edits and refines many drafts before its product is released to the external world of perception. The Multiple Drafts model thereby avoids the tempting mistake of supposing that there must be a single narrative (the "final" or "published" draft) that is canonical--that is the actual stream of consciousness of the subject. There is scope for perceptual as well as temporal variation....and illusion.
In the case of the latter, retroactive “editing” can occur that removes at various points of the “memory arcade” those incidents, verbal outbursts and confrontations the self may not wish to recall, or "own". Voila! One gets a temporal re-constitution of events, or what may be called a “temporal illusion” . The author describes the process thusly:
“Consider… a Stalinesque mechanism: in the brain's editing room, located before consciousness, so there is a delay, a loop of slack, as it were, like the "tape delay" used in broadcasts of "live" programs which gives the censors in the control room a few seconds to bleep out obscenities before broadcasting the signal. . In the editing room, first frame A, of the red spot, arrives, and then, when frame B, of the green spot, arrives, some interstitial frames (C and D) can be created and then spliced into the film (in the order A,C,D,B) on its way to projection in the theater of consciousness. By the time the "finished product" arrives at consciousness, it already has its illusory insertion. “
So, for example, if I am aware of the visual delay effect for most humans and insert an altered image or action in the delay space, I can essentially game the subject's reality and incept a temporal illusion. "Wait a minute! I could have sworn that lady had dark glasses on! Now she doesn't!"
This is the actual meaning and context for temporal illusions. So no, we need not worry that at any time Holmes will suddenly materialize into the past - and escape the not so nice future that awaits him!