it upon the score of their experiments, not upon that of Their
Speculations; for it seems to me, that their Writings, as their
Furnaces, afford as well smoke as light; and do little lesse obscure
some subjects, then they illustrate others. And though I am unwilling
to deny, that 'tis difficult for a man to be an Accomplisht
Naturalist, that is a stranger to Chymistry, yet I look upon the
common Operations and practices of Chymists, almost as I do on the
Letters of the Alphabet, without whose knowledge 'tis very hard for a
man to become a Philosopher; and yet that knowledge is very far from
being sufficient to make him One.
But (sayes _Carneades_, resuming a more serious Look) to consider a
little more particularly what you alledg in favour of the Chymical
Doctrine of the _Tria Prima_, though I shall readily acknowledge it
not to be unuseful, and that the Divisers [Errata: devisers] and
Embracers of it have done the Common-Wealth of Learning some service,
by helping to destroy that excessive esteem, or rather veneration,
wherewith the Doctrine of the four Elements was almost as generally as
undeservedly entertain'd; yet what has been alledg'd concerning the
usefulness of the _Tria Prima_, seems to me liable to no contemptible
Difficulties.
And first, as for the very way of Probation, which the more Learned
and more Sober Champions of the Chymical cause employ to evince the
Chymical Principles in Mixt Bodies, it seems to me to be farr enough
from being convincing. This grand and leading Argument, your
_Sennertus_ Himself, who layes Great weight upon it, and tells us,
that the most Learned Philosophers employ this way of Reasoning to
prove the most important things, proposes thus: _Ubicunque_ (sayes he)
_pluribus eaedem affectiones & qualitates insunt, per commune quoddam
Principium insint necesse est, sicut omnia sunt Gravia propter terram,
calida propter Ignem. At Colores, Odores, Sapores, esse_ [Greek:
phlogiston] _& similia alia, mineralibus, Metallis, Gemmis, Lapidibus,
Plantis, Animalibus insunt. Ergo per commune aliquod principium, &
subiectum, insunt. At tale principium non sunt Elementa. Nullam enim
habent ad tales qualitates producendas potentiam. Ergo alia principia,
unde fluant, inquirenda sunt._
In the Recital of this Argument, (sayes _Carneades_) I therefore
thought fit to retain the Language wherein the Author proposes it,
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