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When Judaism Meets Science
Posts Tagged ‘synapses’
Judaism, Neuroscience and the Free Will Hypothesis (Part 2)
Credit: DARPA
The Jewish assumption of free will is ancient and enduring. But what does modern neuroscience have to say?
The history of neuroscientists’ efforts to explore the free will phenomenon was reviewed in 2016 by philosopher and neuroethicist Andrea Lavazza in the journal Frontiers in Human Neuroscience. The setting for our current understanding was drawn a half century ago with the discovery by Hans Kornhuber and Luder Deecke of the Readiness Potential (“RP”), a measurement of increased bio-electric activity in the brain. The RP was measured by an electroencephalogram (“EEG”), a procedure in which electrodes were placed on a subject’s scalp to allow for the recording of bio-electric activity. This activity was seen as an indication of preparation for a volitional act.
One question raised by the discovery of RP was whether an individual was conscious of an intention to act before RP appeared. In the early 1980s, Benjamin Libet, a son of Jewish immigrants from Ukraine who became a neuroscientist at the University of California-Davis, sought to answer that question. Libet and his team designed a relatively simple test. First, subjects were wired for an EEG. To record muscle contraction, electrodes were also placed on subjects’ fingers. Then the subjects were asked to do two things, spontaneously move their right finger or wrist, and, with the aid of a clock in front of them, report to researchers the time they thought they decided to do so.
What Libet found (Libet et al. 1983) was that conscious awareness of the decision to move a finger preceded the actual movement of the finger by 200 milliseconds (ms), but also that RP was evident 350 ms before such consciousness. While Libet recognized that his observations had “profound implications for the nature of free will, for individual responsibility and guilt,” his report appropriately contained several caveats. First, it noted (at 640) that the “present evidence for the unconscious initiation of a voluntary act of course applies to one very limited form of such acts.” Second (at 641), it allowed for the possibility that there could be a “conscious ‘veto’ that aborts the performance . . . (of) the self-initiated act under study here.” Finally (at 641), it acknowledged that “the possibilities for conscious initiation and control” in situations that were not spontaneous or quickly performed. read more
Free Will vs. Deterministic Cause and Effect
For over 3,000 years philosophers and religious thinkers have argued about free will. Some have argued that everything has a material cause that determines all material effects including emotions like fear, love and happiness. Others have argued that there are also subjective mental states like belief, morality and self-identity that influence individual’s reactions to an objective material stimulus.
Now it seems that science has discovered that even worms have free will. If offered a delicious smell, for example, a roundworm will usually stop its wandering to investigate the source, but sometimes it won’t. Just as with humans, the same stimulus does not always provoke the same response, even from the same individual.
New research at Rockefeller University, published online in Cell, offers a new neurological explanation for this variability, derived by studying a simple three-cell network within the roundworm brain. “We found that the collective state of the three neurons at the exact moment an odor arrives determines the likelihood that the worm will move toward the smell. So, in essence, what the worm is thinking about at the time determines how it responds,” says study author Cori Bargmann. “It goes to show that nervous systems aren’t passively waiting for signals from outside, they have their own internal patterns of activity that are as important as any external signal when it comes to generating a behavior.” read more