INTRODUCTION.

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of the false modes of conception, which he mentions un-der this head, is the forming to our selves a fanciful sim-plicity and regularity in natural things. This he illustratesby the following instances ; the conceiving the planets tomove in perfect circles; the adding an orb of fire to the o-ther three elements, and the supposing each of these to ex-ceed the other in rarity, just in a decuple proportion \And of the fame nature is the assertion of Des Cartes,without any proof, that all things are made up of threekinds of matter only b . As also this opinion of anotherphilosopher ; that light, in pasting through different me-diums, was refracted, so as to proceed by that way, throughwhich it would move more speedily, than through any la-ther c . The second erroneous turn of mind, taken notice ofby his Lordship under this head, is, that all men are in somedegree prone to a fondness for any notions, which they haveonce imbibed ; whereby they often wrest things to reconcilethem to those notions, and neglect the consideration of what-ever will not be brought to an agreement with them ; just asthose do, who are addicted to judicial astrology, to the obser-vation of dreams, and to fuch-like superstitions; who care-fully preserve the memory of every incident, which serves toconfirm their prejudices, and let slip out of their minds all in-stances, that make against them d . There is also a farther impe-diment to true knowledge, mentioned under the same head bythis noble writer, which is; that whereas, through the weak-ness and imperfection of our senses, many things are concealed,

1 Apli. 45. I c Ferm.it, in Oper. pag 156, &rc.

Des Cartes Princ. Phil. Part. 3, §. 52. ] d Nov. Org. Aph.46.

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