Medieval Theory of Vision

This post may have relevance to a book I am working on, so if anyone has any ideas or comments or explanations I would very much welcome them.

The ancient Greeks were basically divided into two camps of how vision works. One camp held with the theory of Emission (or extramission) in which visual perception comes from light beams which come out of the eyes. This view was held by Socrates, Plato and many others.

The opposing view held that miniature replicas of objects entered into the eye. This is the intromission theory and was an opinion held by Aristotle, Galen and others. These miniature replicas were called eidola and somehow represented the 'spirit' of the object being viewed.

(In fact there are another couple of theories which are kind of sub-categories of these, but I'm not knowledgable enough to explain the distinctions fully. Here are a couple of interesting articles that I found.

It seems to me that there are several examples in the Gemara which appear to side with the first opinion, that sight comes from light emmitted by the eyes.

For example:
The verse referring to Elisha states (II Melachim 2:24)

וַיִּפֶן אַחֲרָיו וַיִּרְאֵם, וַיְקַלְלֵם בְּשֵׁם יְהוָה; וַתֵּצֶאנָה שְׁתַּיִם דֻּבִּים, מִן-הַיַּעַר, וַתְּבַקַּעְנָה מֵהֶם, אַרְבָּעִים וּשְׁנֵי יְלָדִים.

And he looked behind him and saw them, and cursed them in the name of the LORD. And there came forth two she-bears out of the wood, and tore forty and two children of them

The Gemara explains this in Sotah (46a), stating:

מה ראה אמר רב ראה ממש כדתניא רבן שמעון בן גמליאל אומר כל מקום שנתנו חכמים עיניהם או מיתה או עוני

And he looked behind him and saw them, and cursed them in the name of the Lord. What did he see? — Rab said: He actually looked upon them, as it has been taught: Rabban Simeon b. Gamaliel says: Wherever the Sages set their eyes there is either death or calamity

In other words, it seems that sight has power to cause damage. This source is not conclusive, but how about the story of Rabbi Shimon Bar Yochai when he and his son came out of the cave (Shabbat 33b):

נפקו חזו אינשי דקא כרבי וזרעי אמר מניחין חיי עולם ועוסקין בחיי שעה כל מקום שנותנין עיניהן מיד נשרף

So they emerged. Seeing a man ploughing and sowing, they exclaimed, 'They forsake life eternal and engage in life temporal!' Whatever they cast their eyes upon was immediately burnt up.

Similarly, when Rabbi Shimon saw Yehuda ben Gerim, who was the one who informed the Romans of his words the Gemara says (ibid. 34a)

נפק לשוקא חזייה ליהודה בן גרים אמר עדיין יש לזה בעולם נתן בו עיניו ועשהו גל של עצמות:

Then he went out into the street and saw Judah, the son of proselytes: 'That man is still in the world!' he exclaimed. He cast his eyes upon him and he became8 a heap of bones.

It seems that according to Chazal there is a fire that comes out of the eyes, which is normally weak, but when coupled with strong spiritual force it can become an actual fire and burn things up.

The truth is that I understand that the concept of ayin hara is also based on this worldview. I know that nowadays we tend to explain it as based on jealousy of others, but if so, why is there no concept of 'ozen hara'? It seems that actually looking at something has power to cause damage. Conversely there is a saying that:

וא"ר יצחק אין הברכה מצוייה אלא בדבר הסמוי מן העין

R. Isaac also said: A blessing is found only in what is hidden from the eye, for it is written, The Lord shall command the blessing upon thee in thy hidden things. The School of R. Ishmael taught: A blessing comes only to that over which the eye has no power, for it is said, The Lord shall command the blessing upon thee in thy hidden things.

All of these sources imply (to me) that the eye emits some force which can cause physical damage if not channeled properly.

(I know that Superman had similar powers - where do you think he got the idea from?)

Rashi in Chumash is explicit that this is how sight works. In parshat Haazinu (Devarim 32:10) the verse states:

יִמְצָאֵהוּ בְּאֶרֶץ מִדְבָּר וּבְתֹהוּ יְלֵל יְשִׁמֹן יְסֹבְבֶנְהוּ יְבוֹנְנֵהוּ יִצְּרֶנְהוּ כְּאִישׁוֹן עֵינוֹ

He found them in a desert land, and in a desolate, howling wasteland. He encompassed them and bestowed understanding upon them; He protected them as the pupil of His eye.

Rashi explains:

"כאישון עינו" - הוא השחור שבעין שהמאור יוצא הימנו"

as the pupil of his eye: This refers to the black part of the eye, from which the light comes outward.

I haven't yet found the source of Rashi's statement in Chazal. Perhaps one of you knows whether Rashi took this explanation from an earlier source, or it is his own chidush. Also I have looked, but not yet found, whether any of the commentaries on Rashi manage to explain this in accordance with modern theories of sight (i.e. that light comes from a light-source, is reflected off objects, and then enters the eye).

And what is also interesting is that both Rabbeinu Bachye (on the verse) and Meiri (in his commentary on Tehillim 17) seem to side with the other theory of sight, and say that the word ishun means pupil because of the 'little man' (ish) that can be seen within it. This seems to be the theory of eidola, that reflections leave the object and enter the eye. Again, I cannot find a source in Chazal for their commentary, but I would be glad if someone could find one for me.

It apears that the modern theory of sight first developed in the end of the 10th century and beginning of the 11th by Abu Ali Mohammed Ibn Al Hasn Ibn Al Haytham, whom we know today as Alhazen. However, since he lived mainly in Cairo, and wrote in Arabic, his works would have been unknown to Rashi, Rabbeinu Bachya or Meiri. But they should have been known to those who came not much later. Which is why I would expect later commentaries on Rashi (particularly) to explain him according to the 'modern theory.'

Rashi had ruach hakodesh

The Artscroll Gemara, unlike Steinsaltz and other English or Hebrew translations/commentaries, have set themselves the task of always following Rashi's explanation, even if it is not the simplest. You may have noticed this when the magid shiur in daf yomi tries to give Tosefot's explanation of a sugya which is easier than Rashi's, and everyone with an Artscroll Gemara argues that he is saying it wrong.

There is a sugya in Rosh Hashana 24a regarding the position of the moon in relation to the sun, and the difference between winter and summer.

Artscrolls team of Rabbis (18 names are listed in the beginning of the book) struggled to understand Rashi here. Eventually they were forced to write the following:

The facts of this explanation simply to not comforn to the basic astronomical data as we know it. According to simple ovservation, the new moon does not set at one place year round. On the contrary, its setting place is very close to that of the sun; namely, south of due west in the winter and north of due west in the summer. Furthermore, its north-south postion in relation to the sun does not depend on the season of the year but rather on other considerations (see Rambam, Hil. Kiddush HaChodesh 16:7 ff.). Unfortunately, the holy words of our master Rashi here are beyond our feeble understanding and they await elucidation.
...
Rashi's explanatino aside, the Gemara can be explained quite simply...
 

 In other words, the translators and editors of the Artscroll Gemara were unable to understand how Rashi's explanation of the Gemara fit with reality. Since that reality can be ascertained by "simple observation" it is inconceivable that Rashi didn't know it. It is not a question of modern science or even geography. Furthermore, Rashi left aside the simple understanding of the Gemara to write his difficult explanation that cannot be understood.

There are only two possible ways of understanding Rashi. Either he didn't know basic astronomy. Or he wrote his commentary with such deep Ruach HaKodesh that it can not be understood by modern talmidei chachamim.

Since the first option is inconceivable, it is clear that Rashi must have been writing with Ruach HaKodesh.

Yarzhreit - R' Shlomo Yitzchaki (Rashi)

Today (28th Tamuz) is the yarzheit of probably the most famous and most influential of all Ashkenazi Rabbis - Rashi. Arguably he is still the most influential Jewish author since the time of the Talmud. It is virtually impossible to move in the world of Chumash (and Nach) or Talmud without Rashi's commentary.

He wrote on almost all areas of Torah, and was one of the first to write a linear commentary on the Torah and Talmud.

This is a small part of the wikipedia entry for Rashi (there is much more there which is recommended reading:

Rabbi Shlomo Yitzhaqi (Hebrew: רבי שלמה יצחקי), better known by the acronym Rashi (Hebrew: ‏רש"י‎), (February 22, 1040 – July 13, 1105), was a rabbi from France, famed as the author of the first comprehensive commentaries on the Talmud, Torah and Tanakh. Acclaimed for his ability to present the basic meaning of the text in a concise yet lucid fashion, Rashi appeals to both learned scholars and beginning students, and his works remain a centerpiece of contemporary Jewish study. His commentaries, which appear in many printed editions of the Talmud and Torah (notably the Chumash), are an indispensable companion to both casual and serious students of Judaism's primary texts.

Born in Troyes, Rashi departed while in his teens to study at the Yeshivot of Mainz and Worms. He returned to Troyes and founded his own yeshiva in 1067. Scholars believe that Rashi's commentary on the Torah grew out of the lectures he gave to his students in his yeshiva, and evolved with the questions and answers they raised. Rashi completed this commentary in the last years of his life. It was immediately accepted as authoritative by all Jewish communities, Ashkenazi and Sephardi alike. His commentary, which covers nearly all of the Babylonian Talmud (a total of 30 tractates), has been included in every version of the Talmud since its first printing in Italy in the fifteenth century.

Rashi's surname as Yitzhaki, derives from his father's name, Yitzhak. The acronym is sometimes also fancifully expanded as Rabban Shel Israel (רבן של ישראל), Teacher of Israel [i.e. the Jewish People]), or as Rabbenu SheYichyeh" (רבינו שיחיה), our Rabbi, may he live.

May His Soul be Bound in the Bonds of Eternal Life