Hi John,
I do not believe that the Father and Son are the same being. But I do believe they are One because that is what the scriptures teach over and over. They are not two Gods. And I do think the human mind can understand with the Holy Spirit. Remember what Jesus said that there is nothing impossible to God.
Yes God could bring this understanding to any of us, I guess He could take us to the 3rd heaven, like He did Paul and show us. But for now we are having a physical experience and with the Holy Spirit indwelling we do gain spiritual understanding. But at this time that is only as an earnest/guarantee/promise (2Cor 1:22) and it's like we only see through a glass/mirror dimly, it's interesting how the CLV have this verse in 1 Corinthians.
1Co 13:12 For at present we are observing by means of a mirror, in an enigma, yet then, face to face. At present I know out of an instalment, yet then I shall recognize according as I am recognized also."
The word enigma means something obscure or hard to understand. While we are still in the physical I don't think we have anything to point to that can adequately explain this Father and Son relationship/enigma, but God can and does give us a degree of understanding. But until we are actually born into the kingdom and have become spirit beings,and are like Christ, I don't think we can fully understand. But then when we do experience the spiritual realm first hand, we will "see Him as He is."
1John 3:2 Beloved, now we are children of God; and it has not yet been revealed what we shall be, but we know that when He is revealed, we shall be like Him, for we shall see Him as He is.
I think it may take our entering the kingdom, to relate to the Father as Jesus Christ does. But even then it will will just be the beginning, as Christ has had at least 14.6 billion of yrs to come to know the Father, that's the estimated age of the universe. Maybe it will take us a while too, to come to 'know' the Father.
mercy, peace and love
Kat