cauſes, ſomewhat differing from each other, the ſame effect may ariſe; but the true cauſe will be that, from which it truly and actually does ariſe; the others have no place in true philoſophy. The ſame motion of the hour-hand in a clock may be occaſioned either by a weight hung, or a ſpring ſhut up within. But if a certain clock ſhould be really moved with a weight; we ſhould laugh at a man that would ſuppoſe it moved by a ſpring, and from that principle, ſuddenly taken up without farther examination, ſhould go about to explain the motion of the index; for certainly the way he ought to have taken ſhould have been, actually to look into the inward parts of the machine, that he might, find the true principle of the propoſed motion. The like judgment ought to be made of thoſe philoſophers, who will have the heavens to be filled with a moſt ſubtile matter, which is perpetually carried round in vortices. For if they could explain the phænomena ever ſo accurately by their hypotheſes, we could not yet ſay that they have diſcovered true philoſophy and the true cauſes of the celeſtial motions, unleſs they cou'd either demonſtrate that thoſe cauſes do actually exiſt, or at leaſt, that no others do exiſt. Therefore if it be made clear that the attraction of all bodies is a property actually exiſtung in rerum natura; and if it be alſo ſhewn how the motions of the celeſtial bodies may be ſolved by that property; it would be very impertinent for any one to object, that their motions ought to be accounted for by vortices; even though we ſhould never ſo much allow ſuch an explication of thoſe motions to be poſſible. But we allow no ſuch thing; for the phænomen
can by no means be accounted for by vor-
