it, unite with each other, and so coalesce in the same manner, as genuine truths do from induction and analogy. Verbal and grammatical analogies and coincidences are advanced into real ones; and the words which pass often over the ear, in the form of subject and predicate, are from the influence of other associations made to adhere together insensibly, like subjects and predicates, that have a natural connexion. It is in vain to bid an inquirer form no hypothesis. Every phænomenon will suggest something of this kind: and, if he do not take care to state such as occur fully and fairly, and adjust them one to another, he may entertain a confused inconsistent mixture of all, of fictitious and real, possible and impossible: and become so persuaded of it, as that counter-associations shall not be able to break the unnatural bond. But he that forms hypotheses from the first, and tries them by the facts, soon rejects the most unlikely ones; and, being freed from these, is better qualified for the examination of those that are probable. He will also confute his own positions so often, as to fluctuate in equilibrio, in respect of prejudices, and so be at perfect liberty to follow the strongest evidences.
In like manner, the frequent attempts to make an hypothesis that shall suit the phænomena, must improve a man in the method of doing this; and beget in him by degrees an imperfect practical art, just as algebraists and decypherers, that are much versed in practice, are possessed of innumerable subordinate artifices, besides the principal general ones, that are taught by the established rules of their arts; and these, though of the greatest use to themselves, can scarce be explained or communicated to others. These artifices may properly be referred to the head of factitious sagacity, being the result of experience, and of impressions often repeated, with small variations from the general resemblance.
Lastly, The frequent making of hypotheses, and arguing from them synthetically, according to the several variations and combinations of which they are capable, would suggest numerous phænomena, that otherwise escape notice, and lead to experimenta crucis, not only in respect of the hypothesis under consideration, but of many others. The variations and combinations just mentioned suggest things to the invention, which the imagination unassisted is far unequal to; just as it would be impossible for a man to write down all the changes upon eight bells, unless he had some method to direct him.
But this method of making definite hypotheses, and trying them, is far too laborious and mortifying for us to hope that inquirers will in general pursue it. It would be of great use to such as intend to pursue it, to make hypotheses for the phænomena, whose theories are well ascertained; such as those of the circulation of the blood, of the pressure of the air, of the different refrangibility of the rays of light, &c. and see how they
