The following "Tree Lobster" web comic made me think about thinking.
Here is the comic "http://www.treelobsters.com/2011/02/233-answers.html"
And here is my comment:
Humans have the ability to hold in their minds thoughts that can be characterized as "Meta". Additionally they have the ability to think "Self Referentially". The human mind is quite comfortable with both modes of thought. The results of the combination of these two abilities do characterize our mental culture and when we advance to the level of civilization that allows significant "Free-Time" to just contemplate our existence these two features of our mind do give rise to an ever complex world view that we enjoy in the present day. Our failure to validate what we say and think in light of these to very powerful thought methods helps to explain some of our strange beliefs and behaviors.