How Do We Know God Is Incorporeal?

For years I’ve struggled to understand why - with two important exceptions¹ - there seem to be no references in Chazal to Rambam’s 13 principles (as principles rather than just ideas). How can Rambam have been so confident of his position without at least minimal authoritative sources?

As it turns out, Professor Joshua Berman has written a magnificent book that goes some distance towards addressing that question. Berman traces the historical context that likely drove the innovative formalizations of faith² created by Rambam, Saadia Gaon, and R’ Yosef Albo.

But I’m nevertheless still confused about many of the sources in Tanach that the Rambam does quote. For instance, here’s the proof Rambam offers for his third yesod (that God is incorporeal):

והיסוד השלישי הזה הוא מורה עליו מה שנאמר כי לא ראיתם כל תמונה כלומר לא השגתם אותו בעל תמונה לפי שהוא כמו שזכרנו אינו גוף ולא כח בגוף

And this third yesod is testified to by the verse (Devarim 4:15) “For you saw no image”. That is to say, you didn’t sense Him as one with an image for - as we said - He has no body nor any physical aspect.

First of all, I’m not sure how that passage proves that God has no body. It actually only states that no one at Mt. Sinai saw any Divine form - not that no form exists. But the larger question comes from this verse (Bamidar 12:8):

פה אל פה אדבר בו ומראה ולא בחידת ותמנת יהוה יביט ומדוע לא יראתם לדבר בעבדי במשה

Face to face I speak with him [Moshe] and he sees [me] and not through a riddle; and the image of God he sees…

I have no idea exactly what the word תמונה means but whatever it is, it’s absolutely clear that God has one.³ So what did the Rambam mean by using Devarim 4:15 to validate his third yesod?

1. The exceptions are the Divine origin of Torah (Sanhedrin 99a) and the Torah origin of the revival of the dead (Sanhedrin 90b).

2. Professor Berman fascinatingly observes that there isn’t even a word for “faith” in classical Hebrew, Aramaic, or any other Near Eastern language. For example, you won’t find any (relevant) conjugation of ‘אמונה’ as a noun in classical Torah sources.

3. Before you ask: I am aware that the רעיא מהימנא section of the Zohar makes a distinction between these two verses, but that’s a place I’d really rather not go right now. And in any case, that’s not directly relevant to the Rambam’s usage of the Devarim 4:15.