Gain may be temporary and uncertain; but ever while you live, expense is constant and certain: and it is easier to build two chimneys than to keep one in fuel.

All wars are follies, very expensive and very mischievous ones. In my opinion, there never was a good war or a bad peace. When will mankind be convinced and agree to settle their difficulties by arbitration?

If principle is good for anything, it is worth living up to.

The rapid progress of the sciences makes me sorry, at times, that I was born so soon. Imagine the power that man will have over matter, a few hundred years from now. We may learn how to remove gravity from large masses, and float them over great distances. Agriculture will double its produce with less labor. All diseases will surely be cured... even old age. If only the moral sciences could be improved as well. Perhaps men would cease to be wolves to one another... and human beings could learn to be human.

Savages we call them because their manners differ from ours.

Whoever would overthrow the liberty of a nation must begin by subduing the freeness of speech.

"We hold these truths to be sacred and undeniable" in a draft of the Declaration of Independence changes it instead into an assertion of rationality. The scientific mind of Franklin drew on the scientific determinism of Isaac Newton and the analytic empiricism of David Hume and Gottfried Leibniz. In what became known as "Hume's Fork" the latters' theory distinguished between synthetic truths that describe matters of fact, and analytic truths that are self-evident by virtue of reason and definition.