The word heroaken that is translated here as ‘seen’ or 'beheld' in most of the English translations is third person singular of herao which, according to Thayer, has three basic definitions. First, it means to see with the eyes. Secondly, it means to see with the mind, to know, to perceive. Thirdly, it means to become acquainted with through pragmatic experience (The 1981 New Thayer’s Greek English Lexicon, p 451).
If John is arguing from the first definition, this needs to be understood in the light of pragmatic Old Testament examples. We know from the many examples of theophonic manifestations in the Old Testament that God has repeatedly presented himself to man in a number of ways. At times, God availed himself only to man’s auditory senses. He spoke to Adam, to Cain, to Noah, to the Hebrew patriarchs, to Moses, to the prophets, and to others. Sometimes he visited himself upon man in the form of dreams or visions as to the prophet Isaiah in Isaiah chapter six. Other times, he appears as objects such as the cloud or the pillar of fire that went before Israel in the wilderness. Still, there are other times when he visited man in human form. There are some eight accounts of this type of theophany found in the Old Testament. It would seem then that this definition does not fit the evidence of scripture.
The word ‘theophany’ is derived from two Greek words, Theo's meaning God and phona meaning sound or voice. A theophany then is a hearing of the voice of God. Theophonic experiences in scripture assume many forms, yet all seem to have a singular function. They communicate the will of God to man. They provide man with a point of reference that man can comprehend. In so doing, God is demonstrating compassion for the limitations of the human mind to understand things that are beyond his ability to comprehend. In some theophonic experiences, God will accommodate only man’s sense of hearing. One only heard the voice of God. God speaking to Noah in Genesis 6 is just such an example. Another is Genesis 12 where God spoke to Abraham. Sometimes, these theophanies would be accompanied by some type of material phenomenon such as fire, wind, or earthquake as in the cases of Moses in Exodus 3, the nation of Israel in Exodus 13 and Elijah in 1 Kings 19. Each of these accompanying natural phenomena would appeal to a broader range of physical senses as God sometimes chose to speak in these things. Still, at other times, God chose to assume an anthropomorphic form as in Genesis 18 when he appeared to Abraham in the company of two angels, all in human form. For further reference, one might examine these examples of anthropomorphic theophanies. In each case, this is deity appearing in human form. In every example, those to whom The Angel of Jehovah appeared always understood, at some point, that he was God and they honored him as such.
The apostle Paul points out in 1 Corinthians 10:1-4 that Jesus was the Rock who followed Israel through the desert. Therefore, scripture shows us that man has after a limited fashion, experienced God in varying degrees at the sensory level. He has seen and heard God. However, if what John is talking about in verse eighteen is experiencing the essence of God, it is certainly true that man has never looked upon the unshielded essence of the Almighty. Of all men, Moses seems to have been granted the most intimate privilege of experiencing the presence of God in his essence in Exodus chapters 33 and 34. So, this definition does not fit either.
If heroahen is understood as an intellectual limitation, this would seem to fit better with the closing statement of this prologue. “He has explained him.” The Greek word ekagasato is third person singular aorist first indicative active meaning to detail, to set forth in language, to make known or to reveal (George V. Wagram’s Analytical Greek Lexicon of the New Testament, 1983). This is the etymology of our word to ‘exegete.’ “Explained” is the corresponding word to “seen.” In other words, “No man has understood or comprehended God at any time. The only begotten Son who is in the bosom of the Father, he has EXPLAINED him.” The Logos presents God to the mind of man through the medium of human language in such a way that man is now able to understand something of the nature and character of God that he could never know from his observation of the natural world. Only the one who came out of the very presence of God could have done this.
In the 1980 printing of The Expositors Greek Testament on the gospel of John p 692, the expositor makes an interesting observation in contrast to Meyer. He says that ekagasato refers to the “work” which Christ accomplished while he was on earth. This emphasizes a particular function of the Second Position. Having come from this eternal intimate relationship with the Father, he is thus “equipped” to translate the mind of God to the mind of man. The linking of these two minds is intended to create an isomorphic state of thinking. As man begins the process of learning to think and reason as God, he will learn to re-symbolize his relationship both to God and to the natural world. He will have to learn to think differently, to speak differently, and to behave differently. Reality will take on a new definition. This would not be met favorably among the majority of humanity, not in that generation nor in this one.