I was reading a Kindle book by Chuck Smith called "Born Again" and he makes the case that our spirit died (1 Corinthians 15:22) and that we were part spirit.

If you are spiritually dead and out of your environment then you will no longer put life's emphasis on what you don't know but what you do know. So instead of our "spirit" being the default belief, the physical world is our default belief.

http://biblehub.com/1_corinthians/15-22.htm

So how do you make people thirst for the spirit if all they have in front of them is the flesh and worldly pursuits? They don't know what they lost or could have had.