Although I disagree with his position of intuit fides (God elects on the basis of our future faith) and his denial of Christ's active obedience, which man must accomplish rather than Christ (I would have to call such a view heretical); the idea that the Son received his deity from the Father is the same position that the Eastern Orthodox hold, not only that, but the Son and the Holy Spirit receive their deity from the Father. This maintains the unity of the Trinity. If all three Persons of the Trinity were autotheos, I can see how this would lead to Tritheism. I am going to have to dig into this one a little more.
I found this on the Internet:
Calvin argued that ‘when we speak simply of the Son without regard to the Father, we well and properly declare him to be of himself; and for this reason we call him the sole beginning. But when we mark the relation that he has with the Father, we rightly make the Father the beginning of the Son’ (Institutes, I.xiii.19).
Not being a Calvinist, I was not familiar with this dispute among Reformed theologians. I know that the Scriptures proclaim that the fullness of the Deity dwells in Christ, and I certainly proclaim that he is True God, fully 100% God, and that there was no time in which the Son did not exist; however, it is difficult to talk about the Son in exclusion of the Father. In fact, without the Father, he would not be Son. That is in itself a relational term.
I may only be mudding the waters here, and not clarifying anything. This is not a debate with which I am familiar, and so I have more questions than I do answers.