Our Gemara on Amud Aleph tried to determine if a disembodied voice that was heard could be trusted as valid testimony. One of the concerns is this voice may have come from a demon instead of a human, and so a process to discern between a true human or a demon is necessary. The Gemara asserts that a demon’s shadow is different than a human’s shadow. While both may cast a shadow, a human’s shadow is capable of having a shadow on top of it, that is some kind of double shadow.

I hope none of us ever has to meet a demon, but nonetheless I believe this formulation is intriguing and has a deeper meaning. On a basic impressionistic level, a shadow is a representation or a manifestation of a form but not the real thing. The Gemara seems to be saying that a demon can succeed in a degree of human representation but not fully. Almost like an AI that is lifelike and close to passing a Turing test but really cannot.

The Shalah Torah (Shebikhtav Mishpatim Torah Ohr 82) explains this in more depth, based on a fascinating Midrash. By the way, Shalah calls it a Midrash though I have not been able to find it. Interestingly it is quoted by Kedushas Levi (Derashos Lechanukah 16) in the name of the Baal Shem Tov, and alternately quoted by the Nefesh HaChayyim (1:7), also as a Midrash:

The Midrash is based on the verse in Tehilim (121:5): 

ה׳ צִ֝לְּךָ֗ עַל־יַ֥ד יְמִינֶֽךָ

the LORD is your protection (shade) at your right hand

This Midrash interprets the word “Tzell” literally as a shadow, not just a protective shade. God is like a human shadow, and He is only empowered to act in this world based on the energy we bring down through the mystical principle that lower arousal brings upper arousal. In the words of the Nefesh HaChayyim:

וז''ש דוד המע''ה ה' צלך על יד ימינך. היינו שכמו שנטיית הצל של איזה דבר הוא מכוון רק כפי תנועות אותו הדבר לאן נוטה. כן בדמיון זה כביכול הוא ית''ש מתחבר לנטות העולמות כפי תנועות ונטיית מעשי האדם למטה. וכן מפורש במדרש אמר לו הקב''ה למשה לך אמור להם לישראל כי שמי אקי''ק אשר אקי''ק. מהו אקי''ק אשר אקי''ק כשם שאתה הוה עמי. כך אני הוה עמך. וכן אמר דוד ה' צלך על יד ימינך. מהו ה' צלך כצלך. מה צלך אם אתה משחק לו הוא משחק לך. ואם אתה בוכה הוא בוכה כנגדך. ואם אתה מראה לו פנים זעומות או מוסברות אף הוא נותן לך כך. אף הקב''ה ה' צלך כשם שאתה הוה עמו הוא הוה עמך ע''כ.

And what King David said (Tehillim 121): “God is your shadow on your right side,” that is to imply that how an object’s shadow moves is only per the movements of that object, in what direction it moves. By this same metaphor it’s as if He (blessed be His name) joins in to move the worlds based on the movements and intentions of man’s actions below. And so it is explained in the Midrash: “The Holy One (blessed be He) said to Moshe: go and say to them, to Israel, that my Name is ‘I will be as I will be’  What is ‘I will be as I will be’? Just as you are with Me, in that same way I am with you. And so said King David: ‘God is your shadow on your right side’—What is ‘God is your shadow’? Like your shadow. As your shadow, when you felight with it, it delights with you, and if you cry, it cries opposite you, and if you show it an angry or a cordial face, it does the same to you, so too the Holy One (blessed be He) ‘God is your shadow’—just as you are with Him, He is with you.” 

This marvelous tradition and idea has deep psychological import, because it is telling us our behaviors, intentions and thoughts dynamically affect our experiences, and likewise, straight to the upper realms.

Returning to the Shalah, the human being has this capacity, through his actions to arouse the heavenly responses. This is the shadow of the shadow. The demon who is not authentic cannot arouse Hashem, thus its shadow is merely a one dimensional shadow, with no depth.