My previous question on this topic was closed because it required knowledge of the Christian doctrine of the Trinity. To avoid that problem, I am proposing a particular formal definition of the doctrine formulated by Aquinas, and asking whether this formal definition is considered polytheism by Jewish thought.

Basically, he says that there are intelligible relationships within the concept of the deity, which he seems to consider a necessary truth derived from scripture. He gives the example of the deity's word, such as speaking the world into existence in Genesis, and the word must be identical with the deity to preserve divine simplicity. Yet at the same time, there must be a relationship between the word and from whence it proceeds.

Additionally, these relationships cannot be other than the essence of the deity, otherwise that would violate the deity's necessary property of being fundamentally simple in its essence. In other words, these relationships cannot in someway stand outside the deity, or be 'parts' of which the deity is composed.

So, is there anything in this bare logical argument that necessitates polytheism? I'll grant the premise about the deity speaking a word is controversial, but if all the premises were considered correct by Jewish thinkers, would they still somehow be forced to conclude Aquinas' idea still necessitated polytheism?


I apologize this question comes across as awkwardly phrased. I am trying to avoid a couple problems:

  1. Site members having to know another religion's doctrine (Christian doctrine of the Trinity) to answer the question. To avoid this I am stating a specific formulation that is free from knowing anything about Christianity, stated in as plain a language as I can.
  2. Strawman arguments. The majority of Christians believe the Trinity is a single deity, and the Jewish arguments against the Trinity I have seen seem to be against a strawman version, which is certainly believed by some Christians, but I am interested in what the Jewish argument is against the best formulation of the Trinitarian doctrine as consistent with monotheism.

Hopefully, my attempt is successful and doesn't get shut down again. I am genuinely curious, since the doctrine of the Trinity is the main reason why Christianity is considered idolatrous due to polytheism, yet from what I have seen this appears to be an unfortunate misunderstanding, as Aquinas appears to have successfully demonstrated the doctrine of the Trinity is consistent with maximally strong monotheism.


Finally, as a side note, I've noticed other q&as on this site drawing comparison between the Trinity and Sefirot. This is a tangent, but the point is to demonstrate that when we boil things down to their logical essence, abstracting away the religious connotations, it looks like Aquinas actually is saying the same thing as the Sefirot. He only goes one step further and states the mental actions and will of the deity must be a part of its essence (not sub creations) to avoid violating the doctrine of divine simplicity.

Aquinas states there are four different relations based:

  1. on an original intellect (source)
  2. its intellectual activity (word)
  3. the will directing that activity (love)

It doesn't seem like things can get simpler than this, and I see the same divisions in the Wikipedia page on the Sefirot, which seems to be based on the same sort of reasoning. There are:

  1. Keter (source)
  2. intellectual activities (word)
  3. the emotions (love)

Yes, there are more subdivisions within the second two categories that make up the ten Sefirot, but if we are reductionist, in the end we are left with the above three categories that cannot be reduced further.

So my basic point is this abstract formulation of the Trinitarian doctrine, where it is reduced to fundamental conceptual relations independent from any religion and applied to the idea of the deity, seems to exactly agree with Jewish thought that is systematically considering the same thing (with one further step to preserve divine simplicity).

Thus, it is hard for me to understand where the Jewish charge of polytheism is coming from. My only conclusion is that the polytheism charge is against an unrefined notion of the Trinity, that has certainly existed among some Christians, but when we are trying to get to the truth of the matter and not popular opinion, we should deal with the most refined version of a concept.

Any assistance is greatly appreciated!

  • 1
    What you describe in the main body of the question sounds like Pantheism (en.wikipedia.org/wiki/Pantheism)?
    – The GRAPKE
    Jun 1, 2021 at 5:44
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    Yet at the same time, there must be a relationship between the word and from whence it proceeds - why?
    – Harel13
    Jun 1, 2021 at 5:52
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    Didn't you get an answer you approved to your previous question that was closed? Jun 1, 2021 at 13:19
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    @חִידָה thanks for the links. In the Shema prayer article, this is the same strawman issue. Many modern Christians, protestants especially, have a poor understanding of the traditional Trinitarian doctrine. The traditional doctrine would not be compatible with the 'bunch of grapes' description, so the missionaries are not correctly arguing for the Trinity in the first place. That is why in this question I am focusing on a particular clearly articulated formulation of the Trinity from one of the foremost traditional Christian theologians.
    – yters
    Jun 1, 2021 at 17:12

2 Answers 2


During the 1263 Disputation of Barcelona between Nachmanides and the Church of Aragon, Nachmanides was asked about the trinity (translation from the Jewish Encyclopedia):

"Fra Pablo asked me in Gerona whether I believed in the Trinity."

He answered:

"I said to him, 'What is the Trinity? Do three great human bodies constitute the Divinity?' 'No!' 'Or are there three ethereal bodies, such as the souls, or are there three angels?' 'No!' 'Or is an object composed of three kinds of matter, as bodies are composed of the four elements?' 'No!' 'What then is the Trinity?'

He said: 'Wisdom, will, and power' [comp. the definition of Thomas Aquinas cited above].

Then I said: 'I also acknowledge that God is wise and not foolish, that He has a will unchangeable, and that He is mighty and not weak. But the term "Trinity" is decidedly erroneous; for wisdom is not accidental in the Creator, since He and His wisdom are one, He and His will are one, He and His power are one, so that wisdom, will, and power are one. Moreover, even were these things accidental in Him, that which is called God would not be three beings, but one being with these three accidental attributes.'

Our lord the king here quoted an analogy which the erring ones [the Christians] had taught him, saying that there are also three things in wine, namely, color, taste, and bouquet, yet it is still one thing.

This is a decided error; for the redness, the taste, and the bouquet of the wine are distinct essences, each of them potentially self-existent; for there are red, white, and other colors, and the same statement holds true with regard to taste and bouquet. The redness, the taste, and the bouquet, moreover, are not the wine itself, but the thing which fills the vessel, and which is, therefore, a body with the three accidents. Following this course of argument, there would be four, since the enumeration should include God, His wisdom, His will, and His power, and these are four. You would even have to speak of five things; for He lives, and His life is a part of Him just as much as His wisdom. Thus the definition of God would be 'living, wise, endowed with will, and mighty'; the Divinity would therefore be fivefold in nature. All this, however, is an evident error.

Then Fra Pablo arose and said that he believed in the unity, which, none the less, included the Trinity, although this was an exceedingly deep mystery, which even the angels and the princes of heaven could not comprehend. I arose and said: 'It is evident that a person does not believe what he does not know: therefore the angels do not believe in the Trinity.'"

This must have been a winning blow, because Nachmanides then recorded:

"His [Pablo Christiani's] colleagues then bade him [Pablo] be silent."

  • Great answer, although I would say there is a subtlety to Nachmanides' last point. While he is correct that one cannot believe a proposition that is logically impossible, i.e. we cannot believe in square circles and married bachelors, it is possible to believe in propositions which we do not know to be true. For example, an entrepreneur starting a new business does not know it will be successful, but still proceeds because he believes it will be successful. Or, obscure scientific topics, like particle wave duality, that I certainly do not understand in the slightest, but still believe.
    – yters
    Jun 4, 2021 at 12:51
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    @yters I'm not sure your examples are comparable. Those beliefs of the business or science also include knowledge that the outcome may change, it's just that the belief in the outcome not changing is usually something like 99% (a kind of self-denial). Nachmanides I think was speaking about 100% belief - otherwise, we would have to say that angels hold a minimum of 1% doubt in the trinity.
    – Harel13
    Jun 4, 2021 at 13:03
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    That's a good distinction. If the trinity were true, the angles would have to have 100% belief. Can a being have 100% belief that X is true while having 0% understanding of how X can be true? It seems logically possible, but I don't understand how :D
    – yters
    Jun 4, 2021 at 13:45

So apparently Aquinas was born in 1225, well after the main works usually quoted to explain the Jewish viewpoint were written. As they lay it out (Chovos HaLevavos and Rambam in the beginning of Mishna Torah), the very concept of divisibility or G-d having discrete parts is logically impossible. This concept is referred to as Achdus Hashem, or the Oneness of G-d. Thus Rambam explains that while G-d has intelligence, it is not separate or a characteristic as with humans, but part of the nature of his essence. So G-d is still one. That is, his intelligence is not in any way distinct from whatever G-d is.

The Chovos HaLevavos is very clear that when we refer to G-d as one, what we really mean is that he is missing any multiplicity. We cannot know what G-d is, only what he is not, and he is not multiple in any way.

Thus, any verses that seem to refer to G-d having parts are not meant to be understood literally. Verses that say G-d has limbs, emotions, etc. are all metaphorical, because it is a)against our tradition, and b)illogical for G-d to contain any parts or divisibility.

These arguments would seem to leave no room for any kind of Trinity. As the Chovos HaLevavos says, the concept of the unity of G-d leaves no place for multiplicity of any kind. (While the term unity in other contexts can include multiplicity, it cannot here.)

The distinction between true (absolute) unity and conventional unity is as follows.
2The term "one" is derived from the concept of "unity". The term is used in two senses. One of them is mikri (incidental), which is the conventional unity. While the second is in essence and enduring - this is true (absolute) unity.
3Incidental unity subdivides into two divisions. In one of these the character of multitude, collectivity, and aggregation is apparent in it, such as one genus which includes many species or like one species which includes many individuals, and like one man which is comprised of many parts or one army which includes many men.
4Or like we say one Hin (measure), one Rova (measure) or one liter (ex. of rice or water) which contain smaller measures, each of which is also called "one". Every one of these things we mentioned are called "one" conventionally, because the things included under the one name are alike. Every one of them may also be called "plural" since it includes many things which when separated and isolated will each be called "one". Unity in all these manners we mentioned is Mikre (incidental). Each is a unit from one perspective and plural from another aspect.
5The second division of incidental unity is the unity attributed to a single individual, who though seemingly not plural and not a collection of several things, yet is essentially plural, - being composed of matter and form, essence and incident, susceptible to "creation" and "destruction", division and combination, separation and association, change and variation. (see commentaries)
6Plurality must be attributed to anything for which any of these things we mentioned applies to, for they are contradictory to unity. Unity ascribed to anything essentially plural and variable in any way is undoubtedly Mikre (an incidental property). It is unity conventionally, but not in a true sense. Strive to understand this.
7True (absolute) unity is also of two kinds. The first in abstract thought and the second in actual reality.
8The abstract thought version is numerical unity, namely, the root and beginning of all numbers. It is the sign and symbol of a beginning unprecedented by any other beginning. For every true beginning is termed "One", as for example: "And there was evening and there was morning, one day" (Gen. 1:5). Instead of saying "the first day", the verse uses the term "one (day)", because the term "one" refers to any beginning unprecedented by any other beginning. When repeated, it is called "the second", and when repeated again - "the third", and so on until the number "ten", "a hundred", "a thousand", which are also units of new series, and so on to infinity.
9Therefore the definition of number is that it is a sum of units. The reason I called it "abstract thought" is because the notion of number is not perceived by the physical senses. Rather, it is grasped only in thought. It is the "numbered" object alone which is perceptible to the five senses or by some of them.
10The second kind of true unity exists actually. It is that which is neither plural nor susceptible to change or variation, is not described by any of the corporeal attributes, is not subject to "creation", destruction or end. Does not move or waver, does not resemble anything nor does anything resemble it, and is not associated with anything. It is from all possible perspectives - true Unity and the root of everything plural. For as we already pointed out, unity is the cause of plurality.
11The true unity has neither beginning nor finiteness because anything which has a beginning or finiteness necessarily must be subject to origination and destruction. And anything subject to these is also subject to change, and change is inconsistent with Unity. Hence, it would be more than one since it had existed as one thing and then changed into a different thing, and this necessarily implies plurality.
12Similarity is also an incidental property (mikre) in anything which is similar (to something else), and whatever has an incidental property is plural. But absolute unity, in its glorious essence, is not subject to any incidental properties whatsoever in any respect.
13If one will claim that the quality of "unity" is itself an incidental property in the Absolutely One. 14We will answer this as follows: The ascribing of true unity is intended to express the exclusion of multitude and plurality. When we describe Him as One, we mean only the negation of any multitude or plurality. But the true Unity, cannot be described by any attribute that would connote in His glorious essence any plurality, change, or variation. With this we have completed our words, regarding the true unity and the relative unity. Note it well.

In your characterization of Aquinas, he seems to be going for a paradox: G-d is one and indivisible, while also being three. The impossibility of this making sense is also described in the Chovos HaLevavos:

The fourth argument: We will say to anyone who thinks the Creator is more than one as follows. It must be that the essence of all these (supposed creators) is either one or not one.
25If you say, that in essence they are one, if so, they are one thing, and the Creator is not more than one.
26If you say that each one of them is, in essence, different from the other, it must therefore be there is some distinction between them due to their difference and non-similarity. If so, whatever is distinct is limited/bound. And whatever is limited/bound is finite. And whatever is finite is composite - and whatever is composite was brought into existence, and whatever is brought into existence must have a Creator.

That is, in order to say there is a trinity, there must be some way of distinguishing the three entities. At that point they are no longer the true oneness of G-d.

And while they are aware there are verses that indicate against this understanding of G-d, they are not greater challenges to it than the many verses that describe "eyes" or "hands" or other body parts to G-d. The solution is to say they are metaphorical, not that G-d's parts are part of a greater unity. As the Talmud says

Rabbi Yehuda says: One who translates a verse literally is a liar, since he distorts the meaning of the text, and conversely, one who adds his own translation is tantamount to one who curses and blasphemes God.

So implicitly, when faced with verses that create greater challenges than the one posed by Aquinas, they rejected his answer as heretical, and insisted that it would be erroneous to follow the literal meaning of the verses.

In addition, if Aquinas believed that the historical Jesus was part of the Trinity, all of this is unnecessary. No amount of rhetorical handwaving can make considering a flesh-and-blood person divine anything other than idolatry.

  • Thanks, that makes a lot of sense. The doctrine of the Trinity didn't become spelled out in philosophical terms until centuries after Jesus' life, although the doctrine itself was explicit in Jesus' command at the end of Matthew. So it makes sense there were no philosophically rigorous formulations to respond to.
    – yters
    Jun 3, 2021 at 21:35
  • From what I understand Aquinas says the persons of the Trinity are grounded in relationships, which are real distinct things, but not parts. That is his way to resolve the apparent contradiction of three things in one fundamental unity.
    – yters
    Jun 3, 2021 at 21:43
  • Per your last point, this is also a deeply theorized topic, which I grant you will probably consider to be 'rhetorical handwaving.' For what it is worth, traditional Christians would agree with your last point. Aquinas says that Divine and human nature were not combined in essence, but in an inbetween thing called the hypostatic union. I don't really understand this. Maybe it is wrong. But it seems at least possible for the deity to take on humanity without compromising divine unity. Just about all religions affirm the deity interacts with the world.
    – yters
    Jun 4, 2021 at 0:21
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    @yters If they are distinct things, and together comprise one unity, does that not make them parts? Aquinas either has to play fast and loose with his definitions, or go for some kind of paradox. And Judaism says that G-d interacts with the world, but not that He is in any way part of or affected by the world. Rather He affects it in the same way he created it, by pure divine will. Unless you want to claim there is some kind of trinity and are reasoning backward, this point is fairly obvious.
    – N.T.
    Jun 4, 2021 at 2:16

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