But that I ought not any wayes to consent that they should be published during my life; That neither the opposition and controversies, whereto perhaps they might be obnoxious, nor even the reputation whatsoever it were, which they might acquire me, might give me any occasion of mispending the time I had design'd to employ for my instruction; for although it be true that every Man is oblig'd to procure, as much as in him lies, the good of others; and that to be profitable to no body, is properly to be good for nothing: Yet it's as true, that our care ought to reach beyond the present time; and that it were good to omit those things which might perhaps conduce to the benefit of those who are alive, when our designe is, to doe others which shall prove farr more advantagious to our posterity; As indeed I desire it may be known that the little I have learnt hitherto, is almost nothing in comparison of what I am ignorant of; and I doe not despair to be able to learn: For it's even the same with those, who by little and little discover the truth in Learning; as with those who beginning to grow rich, are less troubled to make great purchases, then they were before when they were poorer, to make little ones. Or else one may compare them to Generals of Armies, whose Forces usually encrease porportionably to their Victories; and who have need of more conduct to maintain themselves after the loss of a battail, then after the gaining one, to take Towns and Provinces. For to endeavour to overcome all the difficulties and errours which hinder us to come to the knowledg of the Truth, is truly to fight battails. And to receive any false opinion touching a generall or weighty matter, is as much as to lose one; there is far more dexterity required to recover our former condition, then to make great progresses where our Principles are already certain. For my part, if I formerly have discovered some Truths in Learning, as I hope my Discourse will make it appear I have, I may say, they are but the products and dependances of five or six principall difficulties which I have overcome, and which I reckon for so many won Battails on my side. Neither will I forbear to say; That I think, It's only necessary for me to win two or three more such, wholly to perfect my design. And that I am not so old, but according to the ordinary course of Nature, I may have time enough to effect it. But I beleeve I am so much the more obliged to husband the rest of my time, as I have more hopes to employ it well; without doubt, I should have divers occasions of impeding it, should I publish the grounds of my Physicks. For although they are almost all so evident, that to beleeve them, it's needfull onely to understand them; and that there is none whereof I think my self unable to give demonstration. Yet because it's impossible that they should agree with all the severall opinions of other men, I foresee I should often be diverted by the opposition they would occasion.