Common Sense, initially called Plain Truth, argued that the American colonies should go beyond trying to settle their grievances with England and, instead, become an independent nation. That is its central message.

The colonists had not been thinking about independence as a real possibility before the publication of the pamphlet. People might have talked about it, but that was a far cry from actually pursuing this goal. After the pamphlet was circulated, people began to think: why not?

The radical Paine proposal was that the new nation should be a republic. A republic is ruled by people who were elected by a common vote. Paine rejected the whole idea of monarchy—even a constitutional monarchy—arguing that a monarch was simply a parasite of the state who involved his country in costly wars. He wrote: "Of more worth is one honest man to society and in the sight of God, than all the crowned ruffians that ever lived." A republic at the time was a very radical idea, akin in many people's minds to anarchy.

Paine advocated for independence not only because he thought being tied to a monarchy was a bad idea but also because so many settlers in America were not even English. The settlers, for example. were Dutch, German, French, and Swiss. He argued that a country with such a mix of European ethnicities should not be tied one particular country.

These arguments, put in simple language, helped galvanize the colonists to seek independence.