Category Archives: Benjamin Franklin

Benjamin Franklin

[I]n my first Voyage from Boston, being becalm’d off Block Island, our People set about catching Cod and hawl’d up a grat many. Hitherto I had stuck to my Resolution of not eating animal Food; and on this Occasion I consider’d with my Master Tryon, the taking every Fish a kind of unprovok’d Murder, since none of them had or ever could do us any Injury that might justify the Slaughter.– All this seem’d very reasonable.–But I had formerly been a great Lover of Fish, and when this came hot out of the Frying Pan, it smelt admirably well. I balanc’d some time between Principle and Inclination: till I recollected, that when the Fish were opened, I saw smaller Fish taken out of their Stomachs: Then thought I, if you eat one another, I don’t see why we mayn’t eat you. So I din’d upon Cod very heartily and continu’d to eat with other People, returning only now and then occasionally to a vegetable Diet. So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for every thing one has a mind to do.–

Benjamin Franklin, The Autobiography of Benjamin Franklin, London, 1973, pt. 1

Benjamin Franklin

In the Affair of so much Importance to you, wherein you ask my Advice, I cannot for want of sufficient Premises, advise you what to determine, but if you please I will tell you how.

When these difficult Cases occur, they are difficult chiefly because while we have them under Consideration all the Reasons pro and con are not present to the Mind at the same time; but sometimes one Set present themselves, and at other times another, the first being out of Sight. Hence the various Purposes or Inclinations that alternately prevail, and the Uncertainty that perplexes us.

To get over this, my Way is, to divide half a Sheet of Paper by a Line into two Columns, writing over the one Pro, and over the other Con. Then during three or four Days Consideration I put down under the different Heads short Hints of the different Motives that at different Times occur to me for or against the Measure. When I have thus got them all together in one View, I endeavour to estimate their respective Weights; and where I find two, one on each side, that seem equal, I strike them both out: If I find a Reason pro equal to some two Reasons con, I strike out the three. If I judge some two Reasons con equal to some three Reasons pro, I strike out the five; and thus proceeding I find at length where the Ballance lies; and if after a Day or two of farther Consideration nothing new that is of Importance occurs on either side, I come to a Determination accordingly.

And tho’ the Weight of Reasons cannot be taken with the Precision of Algebraic Quantities, yet when each is thus considered separately and comparatively, and the whole lies before me, I think I can judge better, and am less likely to take a rash Step; and in fact I have found great Advantage from this kind of Equation, in what may be called Moral or Prudential Algebra.

Benjamin Franklin, letter to Joseph Priestley, September 19, 1772