Recently I was involved in a comment thread under an article about religion. I know, it's not a very smart thing to do, but there was one commenter who was berating everyone for their lack of rational thought, while at the same time exhibiting a distinct lack of rational thought. I couldn't resist. I called him out on his fallacies and I was rewarded by being called "muddled-headed" and a "moron". He has yet to respond to my further inquiries. But he did give me substantial fodder that may result in 2-4 blog posts.
"Rational thinking is not dependent on knowledge."
This statement came from one of his replies. From one perspective this seems like a non-controversial statement. Someone's ability to think rationally, the actual mechanism of thinking, is not dependent on knowing certain facts and data. For example, if I wanted to give all of my students a pencil I could rationally plan that out and get the pencils. My ability to rationally think through that problem does not depend on my knowing how many students are in my class. Even if I think there are 15 students, when in reality there are 150, knowing the incorrect number of students may change the way I approach the problem and may cause problems, but that does not impact my ability to rationally think through the problem.
On a larger level, if I thought that the American Revolution was all about "Taxation without representation", and then after reading some books I acquired more knowledge about the causes of the revolution I might change my views about what caused the revolution, but that won't change my ability to think through the new data and reach a new conclusion.
Also, if someone is presented with some new data, it would seem that their ability to incorporate that knowledge depends not on having the knowledge, but on their ability to reason and think through the data. Thus it makes sense to say "Rational thinking is not dependent on knowledge."
So far that statement seems perfectly logical, but if we think about how we actually interact with knowledge and data, that formerly rational statement begins to unravel. My response to that statement was, '"rational thinking is not dependent on knowledge" is akin to saying "breathing is not dependent on air".' Just as breathing requires something there to be breathed in order to make sense, rational thinking requires knowledge in order to work. Knowledge is the stuff that is rationally thought about.
But the connection is deeper than that, because there is some knowledge changes the way we think. This happens both on an individual level and on a societal level. As pointed out by Thomas Kuhn in his book The Structure of Scientific Revolutions, there comes a point where certain data does not fit with our paradigm forcing us to change the way we think about the world. But we may still argue that even a paradigm shift does not change to underlying processes that make our thoughts rational.
For anyone who has learned something profound, we know that what we consider to be rational thought changes throughout our lives. There is certain knowledge that when obtained changes the way we interact with the world. It in effect changes our rational thinking. These experiences are usually profoundly personal. These are the moments when old knowledge takes on new and added meaning, and connections are made between seemingly disparate facts.
In these special cases rational thought does not operate passively on our knowledge, but knowledge and rational thought become co-operative, evolving simultaneously. The original statement given above assumes a certain staticity and independence to rational thought, as if it could operate in a vacuum. But this view leads to an ontological quandary that cannot be resolved without additional data and an evolution in our manner of thinking.