When you get round to watching the ND video by Therese Cory, you might miss if you blink a reference she makes around the 30 second mark to Descartes, the Enlightenment philosopher who turned attention to "the thinking subject". I get the sense from Dr Cory that she thinks this was a good thing (I don't know for sure, it just sounds that way) and I would have to disagree with her on that if so.
First, what does it mean: Descartes split the thinking subject from the thought-about object. In other words, when you think of a nice pasta dinner, you are the subject (thinker) and the dinner is the object (what you are thinking about). If you would like a clear example of how pervasive this thinking today is, just ask yourself: does it sound reasonable? Most of us would say, "Yes. That's reasonable and makes sense."
In fact, it would have horrified the medieval thinker. Indeed, many thinkers today are also horrified by this "turn"!
Why? Because it introduces idealism into our relationship to the world; philosophers and linguists after Descartes would extend this subject/object divide to suggest that you can't actually know the pasta dinner itself, but only what you think of the pasta dinner. In other words, you can only really know your own thoughts, and can never say that your thoughts are one with reality or are accurate descriptions of reality. This is idealism.
If you are interested in going into this deeper, I highly recommend a book by Thomas Nagel called "The View from Nowhere", which is an excellent critique of this Cartesian "turn" (click on the text to find it on Amazon). He also gives an excellent account of how a medieval thinker might have discussed the operation of reasoning and thinking.
There is NO subject/object split in medieval thinking, nor in medieval literature. In fact, as surprising as it may sound, the medieval thinker would argue that your thought of the pasta dinner IS the pasta dinner by analogy.