Theosis, as clasically explained, is a doctrine where humans reach union with G-d. In other words, global organizations like 'The Orthodox Union' one could say, has the very concept of Theosis interwoven into their naming convention. The painting on the Sistine Chapel, attempts, to explain the elaborate and mystical concept through a painstaking and world renowned painting.
A docrine like Theosis, really cannot be explained - the doctrine can only be known. Unfortunately, authors, such as my father, David Graham, attempts to put words on a page in an effort to do a good job for what he was hired for. And, my guess is, somewhere along the way, as pastor of many churches across the United States, he reached a subtle realization of Theosis. Once the doctrine of Theosis is realized and a human is made aware of the ongoing concept existing in every day life, in every interaction, an illumination of the simple animal soul, the Nefesh, reaches beyond the simple, life and death is in the blood concepts. And the purpose, on could say, is to realize the accuracy of the painting on the Sistine Chapel - our meager attempts still have not reached the fullness of the Creator of the Universe. And, as you see in the painting - perhaps the left hand of many was rendered week and the right hand of the Creator was...'chopped off?', no, still reaching. The questions, how does one 'bridge the gap' and perhaps, equally as important what's actually in the space between?