The last lecture posed possibly one of the most intriguing ideas I have heard in a good long while. The idea that many of the worlds conflicts, societies and social systems were born of this simple concept of two opposites balancing eachother out with a result.
If we consider that with every action, there must be an equal an opposite reaction, we can see that with the creation of a thesis, an antithesis is born, and therefore the two will eventually combine to form a synthesis. So when a state or ruling body is formed, there will always be a force opposing it regardless of where or when this happens, in the same way that protons will always exist is there are electrons there to oppose them, and thus the matter is always created. Its a system, which despite countless variables, succeeds to occur time after time after time.
The theory works with most things in the world, and is applicable to even to the smallest of situations.
Thesis: Normal human
Antithesis: Cold wind
Sythesis: Wearing a coat
It can also be applied to higer scale situations,
Synthesis: The Bubonic Plague
It is a succinct system. It is precise and it is true. One thing cannot exist without the other, and there is always a result.