[…] Some hasty and undigested Thoughts, on a Subject I had never before considered, which I set down against our next Meeting, gave the first entrance into this Discourse, which having been thus begun by Chance, was continued by Intreaty; written by incoherent parcels; and, after long intervals of neglect, resum'd again, as my Humour or Occasions permitted; and at last, in a retirement, where an Attendence on my Health gave me leisure, it was brought into that order thou now seest it.