Start by creating dividing a piece of paper with a line and put "Pro" on one side and "Con" on the other.
"Then, during three or four days' consideration, I put down under the different heads short hints of 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 endeavor to estimate their respective weights; and where I find tow, 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 three reasons pro, I strike out the five; and thus proceeding I find at length where the balance lies...I think I can judge better, and am less likely to make 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."