An essay on the powers and mechanism of nature; : intended, by a deeper analysis of physical principles, to extend, improve, and more firmly establish, the grand superstructure of the Newtonian system. / By Robert Young.

  • Young, Robert
Date:
M DCC LXXXVIII. [1788]
Catalogue details

Licence: Public Domain Mark

Credit: An essay on the powers and mechanism of nature; : intended, by a deeper analysis of physical principles, to extend, improve, and more firmly establish, the grand superstructure of the Newtonian system. / By Robert Young. Source: Wellcome Collection.

    127/374 (page 99)
    I C 99. ] i pearance, or event, always, and direQly, pre-^ cedes the effe6l, we (hall have found an experi- ( mental caufe. ' If we can perceive- what it is ; which neceifarily and alone involves that effeft, we fhall have difcovered its rational caufe : for example, impulfe is an experimental caufe of motion, but not a rational one, fince we ,do not perceive how the impulfe of one body invplves the motion of another ; but if befides the im- pulfe, as it appears to fenfe, we can find an idea which does neceffarily, and alone, involve the motion of the impelled body, this idea will be the rational caufe of the motion in this body; it will be TRUE, becaufe the idea perceived being the only one which involves the effeft, that, and no other mufl be the caufe; it will be SUFFICIENT, becaufe it does adually involve the efFe6l. If one, of two diftinft fubftances, pofTeffes a § quality, of which the other is wholly a privation, the union of thefe two fubftances neceffarily implies, in the whole, formed by the union, the prefence of that pofitive quality, which, before . the junction, belonged only to one fubftance. Thus whitenefs being a combination of all the primitive colours, is confidered as a privation of each fingle colour; the union of any primi- tive colour therewith imparts to the whole, thus O 2 united.