we think of our parts or improvements in this part of the world, where knowledge and plenty seem to vie with each other; yet to any one that will seriously reflect on it, I suppose it will appear past doubt, that, were the use of iron lost among us, we should in a few ages be unavoidably reduced to the wants and ignorance of the ancient savage Americans, whose natural endowments and provisions come no way short of those of the most flourishing and polite nations.  So that he who first made known the use of that contemptible mineral, may be truly styled the father of arts, and author of plenty.

12.  In the study of Nature we must beware of Hypotheses and wrong Principles.

I would not, therefore, be thought to disesteem or dissuade the study of nature.  I readily agree the contemplation of his works gives us occasion to admire, revere, and glorify their Author:  and, if rightly directed, may be of greater benefit to mankind than the monuments of exemplary charity that have at so great charge been raised by the founders of hospitals and almshouses.  He that first invented printing, discovered the use of the compass, or made public the virtue and right use of kin Kina, did more for the propagation of knowledge, for the supply and increase of useful commodities, and saved more from the grave than those who built colleges, workhouses, and hospitals.  All that I would say is, that we should not be too forwardly possessed with the opinion or expectation of knowledge, where it is not to be had, or by ways that will not attain to it:  that we should not take doubtful systems for complete sciences; nor unintelligible notions for scientifical demonstrations.  In the knowledge of bodies, we must be content to glean what we can from particular experiments:  since we cannot, from a discovery of their real essences, grasp at a time whole sheaves, and in bundles comprehend the nature and properties of whole species together.  Where our inquiry is concerning co-existence, or repugnancy to co-exist, which by contemplation of our ideas we cannot discover; there experience, observation, and natural history, must give us, by our senses and by retail, an insight into corporeal substances.  The knowledge of bodies we must get by our senses, warily employed in taking notice of their qualities and operations on one another:  and what we hope to know of separate spirits in this world, we must, I think, expect only from revelation.  He that shall consider how little general maxims, precarious principles, and hypotheses laid down at pleasure, have promoted true knowledge, or helped to satisfy the inquiries of rational men after real improvements; how little, I say, the setting out at that end has, for many ages together, advanced men’s progress, towards the knowledge of natural philosophy, Will think we have reason to thank those who in this latter age have taken another course, and have trod out to us, though not an easier way to learned ignorance, yet a surer way to profitable knowledge.