1. JESUS AS GOD
IF Jesus is God (as Christians state in their objective truth claims about him) then he may be examined in exactly the same way as any other Jewish peasant from the first century. This includes using tools dealing with ancient history and archeology as well as science. Science comes into play with such bible verses (claims of objective truth) as Acts 17:28 "in him [God / Jesus] we live and move and have our being". If Jesus is God then it should be possible to empirically prove that all people "lived and moved and have their being" inside a living Jesus while he walked the streets of Nazareth and inside a dead corpse Jesus on Easter Saturday. It should likewise be possible to examine Jesus' DNA and see whether his father was God or Joseph and what DNA God has as his father. Doctors could likewise have examined Jesus' body for any diseases and also produced a Death Certificate including exact cause of death. It should likewise have been possible to examine Jesus' resurrection body and its composition. If today's science in tracking heavenly bodies were know at the time one could have tracked Jesus flying through the sky like Superman to heaven. It should likewise be possible to find out where heaven is by using mathematics to trace the trajectory and speed. Of course, one could also have applied scientific investigation to every miracle and analysed, for example, the water before and after it turned into wine and given a Death Cetrificate for Lazarus and then a clean bill of health after his resurrection.
One could subjectively use bible verses about Jesus.
It seems to me that the ONLY way people know about Jesus as God is through bible verses (either read or interpreted by others) which they view as objective truth.
2. YAHWEH (minus Jesus) AS GOD
If God is infinite and not finite (like Jesus) then it is absolutely impossible for any finite mind or collection of finite minds to fully understand God. [Whereas a human finite Jewish peasant Jesus has the possibility of being able to be fully known.]
God may only be spoken about in metaphor and symbolism. Rather than Kant, the methods of Carl Jung, Joseph Campbell and Paul Tillich are better suited to this search as well as empirical science for if it is true that we "live and move and have our being" in God then God is also within everything that surrounds us and is within us (panentheism). This is also the Hindu concept of Brahman and Paul Tillich's Ground of all being.
In Hinduism, Brahman is the one supreme, universal Spirit that is the origin and support of the phenomenal universe. Brahman is sometimes referred to as the Absolute or Godhead which is the Divine Ground of all being. Brahman is conceived as personal ("with qualities"), impersonal ("without qualities") and supreme depending on the philosophical school. The sages of the Upanishads teach that Brahman is the ultimate essence of material phenomena (including the original identity of the human self) that cannot be seen or heard but whose nature can be known through self-knowledge (atma jnana). - from http://en.wikipedia.org/wi
The human mind is not negated in this search as it is the only tool that we have to use however imperfect it may be. Existence of some supposed supernatural part of the human body that directly communicates to God requires empirical proof and not just bible verses.
Sartre correctly stated "existence precedes essence". Humans create their own values and determine a meaning for their life through consciousness. So, rather than dwelling on what humans consist of in some Christian reconstruction such as tripartite being or as a pinnacle of God's creation, the search for God should be firmly grounded in one's own existence in the here and now. The search includes both external knowledge and also internal self-knowledge for the realm of God with both "within you and without you". (George Harrison)
In WHAT do you "live and move and have your being"? The answers are found through use of the 5 senses and the mind. There is no other possibility. Even if one wishes to argue divine revelation it is still mediated either through the five senses and / or the mind.
HOW do you know what you "know" about God? Our very limited understanding of God can only be known through the five senses and the mind and include investigations within oneself and external to oneself. The understandings include both objective and subjective claims about that in which we "live and move and have our being". These investigations are not only limited to bible verses but includes the totality of reality.
If God is merely a noumenon then he is only a product of your mind with no external reality that can be empirically investigated. Christians try to argue that the subjective assumptions that they perceive in their mind are external realities. However, dreams and hallucinatuions are a similar process and dreams do not have an external reality.
If God is phenomenon then he can be investigated with empirical science. Christians are uncomfortable with the fact that science cannot find God anywhere. Christians wish to limit all investigation of God to the mind saying that the five senses are flawed. The five sense are no more flawed than the mind which can produce hallucinations and dreams that appear to be real but which have no external reality.
By restricting the investigation of God to only the mind Christians have far less than the full amount of tools for the investigation. A proper investigation of God must include all the tools available to humans which are the five senses and the mind. Leaving any one tool out restricts the knowledge of God that is possible.