Common Sense lays out Thomas Paine's philosophy on democracy, freedom, and American independence from Britain. All of his ideas come to us through philosophical arguments, which he says are nothing more than the result of pure reason and common sense.
You can even see his concept of common sense come through the way he writes. You can also see his concept of common sense come through in, well, the title. This text pretty much screams "I am a philosophical work! Hear me roar!"
Common Sense might be a bit tough to read today. Weird words like "shew" keep cropping up all over the place, much like in other awesomesauce philosophical texts of the era (like A Vindication for the Rights of Women) but Paine's writing was as straightforward as it got back in 1776. His audience was thankful for it, too, and they showed their appreciation by snapping up his pamphlets by the hundreds of thousands.
And also by, um, starting the Revolutionary War and founding the United States of America.