A \’Most High God\’ argument against the deity of Christ

Is this a logically valid argument? (That is: does the conclusion follow from the premises?) And is it a sound argument? (That is, is it valid and has only true premises, which means that the conclusion must be true as well?) Yes, it checks out. Here is how we symbolize the argument in predicate logic.

The part in parentheses in step 1 (that this one’s name is “Yahweh”) is unnecessary to get the conclusion, so I’ve left it out of the analysis. The argument has only four steps, three independently-justified premises (1-3) and a conclusion which is implied by them (4).

• Step 1: M_ means that _ has this quality: Most High God. In English, 1 says: There is an x such that x is Most High God and for any y, y is Most High God only if y = x. (In other words, there is at least one Most High God, and there is at most one Most High God—in other words, there is one and only one Most High God. Justification: monotheism—if there is only one god there is only one with this quality: Most High God.
• Step 2: f = the Father. So 2 says: The Father is Most High God. Justification: clear implication of NT texts: 
  Mark 5:7; Luke 1:32, 35, 8:28.
• Step 3: 3 says: It’s not the case that Jesus and the Father are one and the same. Justification: trinitarian traditions (the anti-modalist clause that the Son and the Father are numerically distinct) and/or the fact that according to the NT Jesus and the Father have simultaneously differed, e.g. on a particular Friday night Jesus was dead while the Father was alive. It is self-evident that one and the same thing can’t at one time differ from itself. See here.
• Step 4 (conclusion): 4 says: It’s not the case that Jesus is Most High God. This follows from 1–3; if there is one and only one Most High God (premise 1) and this is the Father (premise 2) and Jesus is numerically distinct from the Father (3), it follows that Jesus is not Most High God. Exactly how we would derive 4 from 1-3 depends on the exact system of logic; I haven’t spelled out those extra steps, since we can all “see” that if 1-3 are true then 4 is true.

Let me then restate the argument in something resembling normal English:

1. One and only one has this quality: Most High God.
2. The Father is Most High God.
3. It’s not the case that the Father and Jesus are one and the same; that is, the Father and Jesus are two.
4. Therefore, it’s not the case that Jesus is Most High God.

4 follows from 1-3 (so it’s valid), and each of 1-3 has ample biblical justification. A Christian should endorse this argument as sound. 

SOURCE: trinities.org