XVIII. Besides the visionary wise people, or those which are such in
appearance only, there are others who have credit given them for being
men of profound knowledge, merely from the mistakes and misapprehensions
of others. He who studies logic and metaphysics in the schools, together
with those other matters, which under the denomination of philosophy are
taught there, notwithstanding the sounding names, of these faculties,
and his being supposed to know every thing, in reality, knows but little
more than nothing. It is commonly said, that such a man is a great
philosopher, when in truth he is no philosopher at all, either great
or little. All the ten categorical principles, together with the whole
contents of the eight books on physics, and their two adjuncts _on
generation and corruption_, put into a logical alembic, would not produce
a drop of true philosophical spirit, that would assist us to explain the
most vulgar phenomenon in the sensible world. The Aristotelic ideas,
have no more to do with physics, than the Platonic ones; and the physics
of the schools, are pure metaphysics. All that the Peripatetics have
hitherto written or disputed concerning motion, has not determined, what
is the line of reflection, by which a ball returns back that is struck
against a wall, or what is the degree of velocity, with which a heavy
body descends by an inclined plane. He who by the ordinary metaphysical
reasonings, thinks to attain a true knowledge of nature, is as mad, as he
who should fancy himself master of the world, because he is possessed of
a map of it.
XIX. The great advantage of these philosophers in name, if in the schools
they manage with dexterity the rules of science, consists in this, that
in virtue of the four species or rudiments of theology or medicine
they acquire there, they are enabled to dazzle the eyes of mankind,
and to pass in the world, for great theologians and doctors of physic.
With respect to theology, the mistake in this matter is not so great;
but with regard to medicine, it cannot be greater. By the rule, _Ubi
desinit physicus, incipit medicus_, it seems as if it should follow of
course, that a good philosopher is easily made a good doctor of physic.
Upon this supposition, when people see a practising physician, who has
twenty syllogisms at his fingers ends, ready to explain and demonstrate,
whether privation is a principle annexed to a natural entity, or whether
the united mass or the whole, can be of a distinct or different texture
from the parts, they fancy he is possessed of all the requisites and
recommendations, that are necessary to establish and fix him as a most
able, or first rate man in his profession.
XX. That most learned commentator upon Discorides, Andrew de Laguna,
says, that if it could conveniently be done, it would be good policy
to send those flaming young physicians, who are just come from the
university, brimful of the bragadocio arrogance of _ergo_ and _probo_, to
practise physic in those nations we are at war with, for that it would be
attended with a great saving, both of men and money, to our own country.
XXI. I can with confidence affirm, that there is no art or faculty,
that can be less conducive to the acquisition of medicinal knowledge,
than the physics of the schools. If all the philosophers that are,
or ever were in the world, could be convened together, and remain in
consultation for a hundred years, they would not in all that time, by the
mere help of philosophical speculations, be able to instruct us how we
should cure a chilblain; nor from that tumultuous consultation, should
we obtain any maxim, that ought not to be prohibited as contraband, and
refused admittance into the chamber of a sick person. Good sense joined
to experience, either acquired by a man’s own, or the practice of other
reputable people, are both the father and mother of medicinal knowledge;
nor has physics, that is to say the physics of the schools, the least
share in the propagation of this species.
XXII. The reasoning of naturalists upon all kinds of mixtures,
consists, in whether they are constituted of matter and substantial
forms according to the doctrine of Aristotle, or of atoms according
to that of Epicurus, or of salt, sulphur, and mercury, according to
that of the chymists, or of the three elements, according to that of
the Cartesians: whether these are composed of undivisible points, or
of parts dividable _in infinitum_; whether their action or operation
is from their texture, or the motion of their particles, or from some
accidental virtues which they call qualities; whether these qualities are
of the manifest or the occult kind; and whether they are of the first,
second, or third class or species. Now what has all this to do with
medicine? I will venture to pronounce no more, or rather less, than it
has with geometry or jurisprudence. When a physician goes about to cure
a tertian ague, all this farrago of questions applied to the operations
or effect of the bark, is of no sort of use to him. The only thing that
is of any importance for him to know, is, whether his experience has
taught him, that in the present state of the disorder, it will be proper
to administer this febrifuge; but this he is to infer, not from the
maxims, _dici de omni, dici de nullo_; but from conviction, drawn from
experiments he has made himself of its efficacy in the like cases, and
also from those, which have been made by physicians of eminence who have
wrote on the subject.
XXIII. In no art whatever, is it of any use, to have a physical knowledge
of the implements, with, or by which, a man does his business. A man
may be an excellent pilot, without being able to explain the directive
virtue of the load-stone to the pole; and a great soldier, although he
is totally ignorant of the physical component parts of gunpowder, and
the metal with which military implements are made; and he may be a great
painter, without knowing whether colours consist of intrinsic accidents,
or whether they are produced by the various reflections of light. Nor
does the being able to argue well upon these points, conduce in the
least degree, to make a man either a pilot, a soldier, or a painter. But
there is no necessity for my enlarging further, in order to extirpate
this common error from the world, as the learned Doctor Martinez, has
fully and effectually exploded it in his two volumes, intitled Medicina
Sceptica.