A couple of lesser known quotations from Benjamin Franklin

The art of concluding from experience and observation consists in evaluating probabilities, in estimating if they are high or numerous enough to constitute proof. This type of calculation is more complicated and more difficult than one might think. It demands a great sagacity generally above the power of common people. The success of charlatans, sorcerors, and alchemists — and all those who abuse public credulity — is founded on errors in this type of calculation.
Benjamin Franklin and Antoine Lavoisier, Rapport des commissaires chargés par le roi de l'examen du magnétisme animal (1784), as translated in "The Chain of Reason versus the Chain of Thumbs", Bully for Brontosaurus (1991) by Stephen Jay Gould, p. 195

The small progress we have made after four or five weeks close attendance & continual reasonings with each other - our different sentiments on almost every question, several of the last producing as many noes as ayes, is methinks a melancholy proof of the imperfection of the Human Understanding.


We indeed seem to feel our own want of political wisdom, since we have been running about in search of it. We have gone back to ancient history for models of government, and examined the different forms of those Republics which, having been formed with the seeds of their own dissolution, now no longer exist. And we have viewed Modern States all round Europe, but find none of their Constitutions suitable to our circumstances.


In this situation of this Assembly, groping as it were in the dark to find political truth, and scarce able to distinguish it when presented ot us.
Benjamin Franklin's speech to the Constitutional Convention, June 28, 1787

I confess that there are several parts of this Constitution which I do not at present approve, but I am not sure I shall never approve them. For having lived long, I have experienced many instances of being obliged by better information, or fuller consideration, to change opinions even on important subjects, which I once thought right, but found to be otherwise.
Benjamin Franklin to the Constitutional Convention, 1787