Not can, but do
If we still have the concept of I at play in our everyday lives then we are surely filled with demons. Only a demon can say, "I want this, I like this, I crave that, etc."
"Woe to you, captives, for you are bound in caverns! You laugh! In mad laughter you rejoice! You neither realize your perdition, nor do you reflect on your circumstances, nor have you understood that you dwell in darkness and death!" -- The Book of Thomas the Contender
In order to be set free from this prison called Earthly life, we must completely die to ourselves in this instant. For where is the Kingdom of Heaven found, if not in this instant?
You may find the book "Revolutionary Psychology" beneficial to your spiritual quest --
http://www.gnosticweb.com/documents/EN_Revolutionary_Psychology.pdf
All the strength.