The Divisible Brain

Question from Ratburn:
In 2017, two scientists did tests with split brain patients, and even with the left and right hemisphere severed, there still seemed to be a unified consciousness. Here is the actual study:

Here is an article which elaborates on it:

Would love to get some insight.

Answer by SmartLX:
The implication here is that split-brain subjects behaving more normally than first thought possible may contradict materialism, as two separate halves of the brain are still somehow communicating and functioning as one consciousness. Red flag right off the bat: this is an argument from ignorance if one were to make it directly, because the mere absence of an explanation is used to assert the influence of the supernatural. Even if it sounds convincing subjectively (not to everyone, by the nature of subjectivity) it can’t be called logical until every natural possibility is ruled out. In this way it’s similar to the mysteries of consciousness itself.

That said, here are some points that make it sound less convincing.
– From the article: once the main link is severed, “the hemispheres have virtually no means of exchanging information” (emphasis mine). If there is any means at all, it will be working overtime to compensate for the lost connection as much as possible. This is what the brain does to cope with any injury, as described in this article from Carnegie Mellon University.
– The classic experiment is to put objects in different hands for the subject to describe. A lot of the writing is ambiguous about whether the opposite eye is blocked off for this; if the side of the brain that controls talking gets any information for itself it may be able to learn to process it independently.
– See this response from Neuroskeptic: the subjects had been brain-split for decades, giving every opportunity for the brain to knit itself back together, functionally or structurally, any way it can. The author of your article is one of the authors of the study, which admits this.

4 thoughts on “The Divisible Brain”

  1. Argument from ignorance is the worst possible logical fallacy in a human being and it is the very one that enables religiosity to flourish.

    In the case of religion, it states there is god because humans cannot explain the origin of matter, or energy for that matter, so, it follows that it is god that created energy from nothing.

    Energy become matter.

    After that all was piece of cake.

    But, it is not what follows from the premise. It only proves how vain humans are, because their ‘logic’ is that if THEY cannot explain and/or understand something, THEN it must be a supernatural power.

    But that conclusion does not follow from the given premise.

    What follows from the given premise is that human brain evolved on the Earth, to serve humans in their survival, finding food, sex mate and shelter, but not to understand the origin of energy in space and matter thereafter.

    This is why only fools are on position 1 and 7 of Dawkins’ scale of (ir)religiosity, those folks that say they are deadly certain there is god, position one and those who are as much sure as the former, that there is no god, on position seven.

    Dawkins himself is on position six, as am myself. We both are only human and our brains have no capacity to understand the origin of the Universe, however smart they are. I humbly say I am not smart enough to understand such things…and many other things, as is, just one example, human idiocy… and then I go on with my life. God or no god I know I will die one day forever.

    Because, religiosity is about fear of irreversible and forever death.

    No more and no less. Nothing else but simple fear of death. Scary but so.

  2. I don’t see how this is considered an argument from ignorance. The authors never claim or even imply a supernatural explanation for their findings. They offer evidence that split brain individuals continue to have one consciousness. They provide “what” they found not “why” they found it and they don’t rule out natural causes as SmartLX has previously noted.
    I would like to know if Roger Perry really considered a person with a split brain as two separate entities. Did he get permission from both to do his experiment, or did he only need one signature? Did he call them by two names or one? Is this phenomenon recognized legally in a court of law? For instance if the patient gets married is the spouse considered a polygamist? If the patient killed themselves would it be considered a suicide or a homicide? Two death certificates? Two names on the gravestone?
    I know these questions seem absurd but isn’t that because Sperry’s claim of dual consciousness within one person is absurd?

    1. To clarify, James, it’s an argument from ignorance only if it IS used (by the authors or by anyone referring to their work) as support for souls, gods or any supernatural means of communication between the halves of the brain. The fact that a subject has appeared on Ask the Atheist usually means someone is at least trying to imply this.

Comments are closed.