I am an Atheist.. but not so bias as to dismiss everything and anything related to religion. Think about it.
1. The fact that this may make no sense to you isn't reason enough to say it can't be true.
It would prove at most that somewhere in the history of the bible (it didn't start in english) someone translated an idea as mentioned.
If you would like a factual account of where, I happen to know it was a concept first introduced in England when King James collaborated with the church who comissioned 11 men to rewrite the bible for political/clerical reasons...
Even this though would only suggest that the Anglican church has a history of weirdness or confusing interpretations... and maybe you could form the hypothesis that they make things up.
Now
2. Assuming "the father," the son," and "the holy ghost" were one before the King James Version of the Bible... it would be in Greek or Hebrew.
If you trace the origins of the term "holy ghost" you will come up with a historical linguistic translation of
Holy Ghost [ ghost, i.e., spirit, a translation of Gr. pneuma =breath, air
Holy Spirit or Holy Ghost [ ghost, i.e., spirit, a translation of Gr. pneuma =breath, air], in Christian doctrine, the third person of the Trinity . The Holy Spirit is sometimes defined as the aspect of God immanent in this world, in human beings, and in the church. Jesus' promise to his disciples of a Comforter (or Paraclete, i.e., advocate), in John 14, is considered his principal reference to the Holy Spirit, and the descent of the Holy Spirit on the apostles and the communication of the gift of tongues, as recounted in Acts 2, is thought to be an example of the work of the Holy Spirit in time.
So this idea essentially embodies, breath or life (existence), the spirit of being and the "gift of tongues" that permits us to communicate it (that would be, in scientific terms, the human condition that distinguishes us from all other walks of life), and the infinite and vast universe which puts man in a state of awe and humility (that which some people refer to as god).
See it how you want. But don't be so stubborn that you don't see substantiation in what you assume without reason is nonsense. Not everything that ever came out of a religious mans mouth is stupid. It is the way we conceptualize this and how we incorporate it into our lives that makes the difference between a theists and atheists... it is a theology, a theory of the history of things... that's not the wrong of christians anymore than it is human to do so.
Frusturation is fine... but if you find other people's theories inadequate find your own rather then telling people how stupid their theories are. If you don't believe that god and the church govern your life then don't blame them for your confusion,
I didn't mean anything cruel by this, I just found it poignant to be frank. Questions are good... but logical and rational behavior isn't produced via skepticism alone... don't take anything for granted, of course, but even worse is to rule out something because you take for granted it is wrong... you'll never know if you really know what you're talking about if you don't set up some system of principles and stick by them.