Sea Breeze : Unitarians frequently state that 1+1+1 = 3 not one. Yet they have no problem believeing that H2O can exist as a solid, gas, or liquid and yet be one substance.
A belief that Jesus, like water, can exist in three states but remain the same substance is the "heresy" of modalism, or Sabellianism, which teaches that God is one person appearing in three different modes. This was held by some early Jewish Christian groups but is generally held to be heresy by orthodox christianity today.
I concur with peacefulpete that if you want to discuss the nature of man it would be more productive to start a thread on it yourself.