I’m currently working on a book on decision mapping (and more generally, deliberative decision making), tentatively called Draw the Right Conclusion!.  I’ll be periodically releasing draft chapters.   First cab off the rank is the Introduction.

Comments and suggestions most welcome.

Here are the opening paragraphs:

In late 1772 Joseph Priestley was wrestling with a mundane problem.

Over a period of just a few years, Priestley had transformed himself from a little-known minister and teacher in towns of northern England into one of the most important scientists of his day.  He had published the History and Present State of Electricity, the first compendium of scientific knowledge in this new field, and the dominant textbook for the next hundred years.  His recent investigations had revealed one of the most profound aspects of life on earth: that plants make the air fit for us to breathe.  This work earned him the Royal Society’s Copley Medal, the Nobel Prize of his day.  Soon he was to isolate the substance that plants were providing, thereby playing a crucial role in the discovery of oxygen.

Yet the dilemma causing him so much anxiety was of a kind any of us might recognize.  Should he move with his young family from Leeds to Wiltshire?  He had been offered a kind of patronage by William Petty, the controversial Earl of Shelburne.  Shelburne would house the Priestleys at his estate, Bowood, and provide Joseph with a laboratory and time for research.  In return Joseph would be required to act as tutor to Shelburne’s sons and advisor to Shelburne himself.  Priestley had to resolve a personal conundrum laced with unknowns and incommensurabilities.  Would he be sufficiently free to pursue his intellectual passions?  Would his experimentation continue to bear fruit in the new environment?  Did he owe it to his family to accept the greater comfort and security attached to the new position?

Eventually Priestley turned for help to his friend and scientific colleague, the great American scientist and statesman Benjamin Franklin.  Franklin replied in a letter which has become a classic in the theory of decision making:

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 endeavor 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 three reasons pro, I strike out the five; and thus proceeding I find at length where the balance lies; and if, after a day or two of further consideration, nothing new that is of importance occurs on either side, I come to a determination accordingly. And, though the weight of the 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 liable to make a rash step, and in fact I have found great advantage from this kind of equation…

Franklin called this method a “moral algebra”: a kind of calculation, but one suited to human affairs, where often the stakes are large, the alternatives many, the considerations diverse and uncertain, and where your choice will be a test and reflection of your character.

Such as whether to get married, and in particular whether to marry your cousin…

Read the whole draft chapter…