Saturday, February 19, 2011

Ibn Ezra and a theory of memory

Summary: Ibn Ezra following Galenic science as to the functioning of the brain.

Post: In a previous post on Yisro, I highlighted how Ibn Ezra followed Galen over Aristotle in explaining sight, that rays were emitted from the eyes, allowing seeing at a distance. From that same essay, here is another instance in which Ibn Ezra follows Galen over Aristotle. For Aristotle viewed the brain not as the seat of thought, but just as a cooling mechanism for the heart. Meanwhile, Galen was of the opinion that the third ventricle, in the back of the brain, was where memories were stored. This Galenic science was translated and popularized Avicenna, the great Arabian physician, and this is most likely where Ibn Ezra got his medical knowledge.

Ibn Ezra writes:
ודע כי באחרית מוח הראש הוא הזכירה. והמקום מקום משמרת הצורות. והנה הזכירה כוללות השמירה וטעםזכור שיזכור כל יום איזה יום הוא מהשבוע. וכל זה בעבור שישמור היום השביעי שלא יעשה בו מלאכה והנה טעם הזכירה היא השמירה. וכאשר אמר השם: זכור הבינו כל השומעים כי טעמו כמו שמור כאלו בבת אחת נאמרו. ולא הוצרך משה להזכיר בשנית טעם כי ששת ימים עשה ה', כי בתחלה אמר: כאשר צוך ה' אלוהיך כאילו אומר ככתוב בתורתך בדבור זכור, עד ויקדשהו. 
ובעבור שהשם ציווה שישבות העבד והאמה ולא פרש השם למה זה. פרש משה טעמו ואמר זה, שצוך השם שישבות העבד בעבור שתזכור שהיית עבד כמוהו במצרים ויפדך השם. 

Note the memory in the back
And know that in the back of the brain of the head is located the remembering {zechira}. And that place is the place of the guarding of the forms. And behold, the remembering encompasses the keeping {shemira}. And the meaning of Zachor is that he should remember every day what day it is of the week. And all of this is so that he should keep the seventh day, so that he should not perform on it labor. And behold the meaning of zechira is that same as that ofshemira.

And when Hashem said Zachor, all who heard understood that its meaning was like Shamor, as if they were said at one time. And Moshe did not need to mention, in the second {relaying, in Vaeschanan} the reason of "for for six days Hashem made". For in the beginning he said "as Hashem your God commanded you", such that it was as if he had said "as is written in your Torah in the Dibbur of Zachor" until "and sanctify it". And because Hashem commanded that the servant and maidservant rest, and Hashem did not explain why this was, Moshe explains its reason, and said this, that Hashem commanded that the servant rest in order that you recall that you were a servant just like him in Egypt, and Hashem redeemed you. 
To compare to Galenic science:

"The spirit in the third ventricle at the back of the brain operated the power of memory, by which even animals could learn from their perceptions and remember associations."

(Thus, memory is stored in the back of the brain. I'm not sure which of the above corresponds to tzura, but it would seem that Ibn Ezra differs from Galen in which ventricle would contain it.)

Meanwhile, the picture of short-term memory and long-term memory in modern science is a lot more complex. See here.

Thus, Ibn Ezra is not correct, from a scientific standpoint, in what he says about memory. Why am I wasting keystrokes to prove this?

It is not, chas veShalom, to denigrate Ibn Ezra. Rather, my purpose is twofold. First, there are those who elevate Rishonim, together with Chazal, to superhuman status, such that any scientific statement they make is absolutely true. It pays, then, to document with case after case that they relied on contemporary scientific knowledge. Second, as a model to modern-day people who would use madda to understand Torah. Here is a precedent. And mere mention of scientific knowledge is insufficient, since some would just say that they arrived at these true statements via Divine Inspiration. Therefore, it is useful to point out those instances in which they get the science wrong, and where that science corresponds to their contemporary science, for it is in these cases where what the Rishonim are doing becomes clear.


MiG said...

The fact that the Ibn Ezra made a mistake in science would not be relevant to most "non-rationalist" people. For them, the Ibn Ezra is anyways a border-line rishon since he often argues with Chazal. Additionally, that camp believes that Chazal's scientific knowledge derived from mesorah, not from Divine inspiration. They would argue that the Ibn Ezra, like the Rambam, did not necessarily have access to that mesorah.

joshwaxman said...

good point.

still, if i could establish it strongly for one or two Rishonim, and give a few examples for other Rishonim they think would have access to the masorah, then perhaps it could be established more broadly. (e.g., ramban and rabbenu yona accepting that musk, mentioned in the gemara, is initially accumulated blood, like Ibn Ezra and Rambam.)


Z said...

And that place is the place of the guarding of the forms

From here

Occipital Lobe - Region in the back of the brain which processes visual information. Not only is the occipital lobe mainly responsible for visual reception, it also contains association areas that help in the visual recognition of shapes and colors. Damage to this lobe can cause visual deficits

joshwaxman said...

to the commenter who withdrew the comment for some reason:

thanks! this is indeed pretty neat. but i have some thoughts about it, which i'll have to save for another post. in the meantime, you can check out Ibn Ezra on Ki Tisa, regarding the three aspects of Betzalel's wisdom, corresponding to the three areas of the brain, as Ibn Caspi points out.

kol tuv,

joshwaxman said...

ah, you didn't withdraw the comment. I took it out of the spam folder, where Blogger wrongly placed it.

joshwaxman said...

check out my latest post here, on this subject.



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