Dennet dedicates the 6th chapter to discuss consciousness of time. The first question he raises is about an experiment where a person is asked to repeat what they hear from a recording of speech. The person can recount some of what they heard but not all, even though they heard everything. Undoubtedly, the auditory system processed everything the person heard, but why could not they remember the entire recording? The same applies to a visual experiment when someone is shown multiple characters and when asked to remember what they had seen, the subjects can only remember a few characters. Why? Does that have anything to do with time?
Let us return to the two lights experiment. A similar experiment is done when a first stimulus, a circle, appears for 30 milliseconds followed by a ring shape that appears for a longer time. The subject reports that they saw only the second object. According to the Multiple Drafts model, the circle appeared too quickly to be reported. The train that was activated by the circle disappeared and was replaced with another draft.
The main example that Dennett uses to explain consciousness of time is the Battle of New Orleans. The United Kingdom signed a peace agreement to end the war with the United States at the end of December 1814 but the battle happened in January 1815. At the time, it was impossible for a letter to reach all the parts of the British empire quickly so, 15 days after the signing of the treaty, hundreds of British soldiers lost their lives because they did not know the war had ended. Something similar may happen in the brain, because there is no clock to measure the timing of events.
When someone says, “there is a man standing there”, we represent the sentence in our brains without the need to dive into the details of, for example, his feet or his head. Similarly, when representing a “very bright glimpse of red light”, we do not need to divide time to represent the glimpse in our brains. There could be a starting point, a peak, and an end for a period or event, but there is no reason to assume that these milestones would match the time representations we have in our brains.
Time representation, as far as our brain is concerned, is similar to what happens when there is an event that stops the trains of events, or the drafts of consciousness. We can make a representation of time that is similar to real-time when, for example, we need to judge the timing or behaviour of a moving object. If we wanted to know if an object is moving to the left or to the right, or vice versa, we would need to monitor the object for a period of time. Another example of when we need to closely judge events in real-time is when we shoot an arrow toward a moving object.
But how do we represent time in the brain? Are there specific markers or a clock? Not exactly. Dennet uses another example here, which is the clapperboard used by film directors to mark edit points. Actors and crew would see the clapperboard and understand it accordingly. Dennett describes the representation of time in the brain as like a video scene that is empty of any signs indicating time. However, there are multiple acoustic or visual signs that come and mark time like the clapperboard.
Dennett gives another example of how the brain deals with time: what if a non-Japanese-speaking film editor is given Japanese audio to be matched to a video track? The editor can actually do that easily by relying on the audio indicators that he sees in the video, like people talking, without the need to understand Japanese. The optimum way for the brain is to rely on all the existing sources of information, like hearing and vision, to create markers for time and to then make judgments about time.
Time between Libet and Churchland
Dennett dedicates a significant part of his discussion of time to explain and discuss an experiment of Benjamin Libet. Libet’s experiment was very simple: it involved subjects performing actions like hand movements, sitting in front of a timer. They mentioned the time when they become aware of their intention to act, and then they acted. Meanwhile, an EEG recorded their brain activity. At this point in the book, Dennett explains how Wilder Penfield, the pioneer of awake brain surgeries, had discovered that touching some areas in the brain with electrodes can lead to a specific feeling of tingling in the limbs. Libet was doing the opposite, detecting decisions to act, i.e., from brain to hand.
Before explaining Libet’s experiment, Dennett gives another example in the form of a question: who do you think would arrive at an office first, someone who lives outside the city, or someone who lives in the city nearer to the office, given that they are both travelling at the same speed? The assumption here is that the nearer person would arrive earlier. What Libet found is that the people reported their actions after the EEG signal appeared. Libet referred to the time between the action and the EEG as “readiness potential”.
This experiment led to some stir in the non-scientific media – pseudoscience. It has been used falsely as evidence to show a contradiction in the concept of free will and materialism in general. These media used the experiment as evidence of a vague and unconscious motivation that leads to a decision to perform an action.
However, there are some issues with Libet’s experiment. First, the results were totally based on the subjects’ reports. If a subject in the experiment wants to do the action, then they report it, and that happens in the “conscious mental field” as Libet describes it, but not on the neural level. Despite the value of the subjects’ reports and their phenomenology, we should consider returning to heterophenomenology as their experiences shouldn’t be an authority at this level, as Dennett explains. The subjects’ reports are not accurate because they cannot mark time accurately.
Libet had not thought of heterophenomenology, and he concluded that the brain dates the action retrospectively to the initial point of the neuro-response. For Dennett, Libet’s view is Stalinesque because Libet’s explanation of our consciousness of time is based on the correct memory but the wrong consciousness. Others criticised Libet for his attribution of the brain signal to the hand movement while it could be for noticing something else within the experiment settings, therefore the timing could be different.
Patricia Churchland, a neurophilosopher, conducted a similar experiment where subjects verbally reported their sensations of an effect. She found that the time required for the subjects to report these sensations was 375 milliseconds (less than Libet’s 500 milliseconds). Libet had previously described this period as “neural adequacy.”
Churchland objected to Libet’s hypothesis about the brain’s retrospective dating. She also objected to Libet’s reference to dualism and to the problem with causality he referred to. Dennett sees that both Churchland and Libet had fallen into an error, despite Churchland not making assumptions that could encourage metaphysical or pseudoscientific explanations. Like Libet, Churchland assumed that there is some representation of time in the brain, but, in her experiment, she assumed that the error in reporting time happens in subjects’ memory rather than in their consciousness.
One of many similar versions of this experiment is Grey Walter’s (it is worth mentioning that Dennett did not cover all these experiments but he highlighted a few). Walter implanted sensors in the nerves of subjects that detected their desire to press a button before the actual attempt to do so. Walter’s experiment differs from Churchland’s version where subjects say something, and from Libet’s where subjects perform an action. Walter’s subjects were watching something on a screen and were required to click when they saw specific things. By detecting their nervous responses, the time required to report or to do the action is eliminated. Many subjects were surprised and objected that they could not click, and that the images changed before they wanted to click. Here Walter added a new factor to the subjects’ experience, but what did the experiment show? I quote Dennett:
“The fact that the alarm eventually gets interpreted in the subjective sequence as a perception of mis-ordered events (change before button-push) shows nothing about when in real-time the consciousness of the decision to press the button first occurred. The sense the subjects reported of not quite having had time to “veto” the initiated button push when they “saw the slide was already changing” is a natural interpretation for the brain to settle on (eventually) the various contents made available at various times for incorporation of the narrative”.
In summary, there is no temporal sequence of events in our brains as we imagine. At the end of the chapter, Dennett returns to the example of the Battle of New Orleans. He asks again, “when did the British empire know about the peace treaty?” The answer, “it took a range of time that cannot be measured by days or hours.”
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