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LETTER VI.

Of the discoveries of Kepler and Galilec

D ISTINGUISHED above other creatures,by the faculty of reason, and the superi-I Ority of his nature, man is still the slave of pre-Ijudice and opinion, prone to error, and subject1 to continual delusion. Truth and science ad-Ivance by slow degrees; one age destroys the la-Ibours of another, whilst conjecture and hypo-thesis supply the place of argument and demon-Istration. Nature performs her operations con-Isiantly before our eyes, and has furnished us withI the means of tracing their causes and connec-tions ; but the mind, debased by indolence, orI bewildered by superstition, regards these asto-Inilhing scenes with indifference, and considers all■attempts to investigate their causes, as the effectsI of a presumptuous and daring impiety.

From the time of Pythagoras to the sixteenthIcentury, when the true system of the world was■again-revived by Copernicus, the vulgar opinionof the motion of the heavens, and the immobilityof the earth, was generally received; and time,pnstead of discovering its fallacy, served only to' G .

strengthen