136 
imperfection we fhould readily confefs, if a prin- 
ciple of vain glory, cherifhed by that very igno- 
rance, did not prevent us. To give an inftance 
of thefe things, which are in fome fort under- 
ftood by us, I believe phyficians, if they had 
clear and diftin@ ideas of the ftructare of our 
bodies, and of the motions of the blood, and 
other juices belonging to them, would be able to 
mend radically any unnatural difpofition in thefe 
parts, as they could then prove the validity of 
fuch clear and diftin&t ideas, by reducing them 
to the teft of experiments, which is allowed in 
every country to deferve credit, more than reafon 
itfelf. But as hitherto they are very unhappy in 
their attempts to cure our diforders, and are al- 
ways perplexed by crofs events, from the weak- 
nefs of their reafonings; we cannot but allow 
from this, and all, that the great Defcartes has 
beftowed no commendations on experiments 
which they do not highly deferve. 
It is plain, from what has been faid, that 
fomething may exift in the underftanding, which 
never before had been taken notice of by the 
fenfes, tho’ we cannot comprehend them clearly 
and diftin€tly, unlefs they terminate in the fenfes, 
or at leaft may effectually terminate in them. 
Befides, our underftanding becomes at length 
{o difcerning, as through a frequent and atten- 
tive cbfervation of experiments and fenfible ef- 
feéts ; fometimes we are enabled to judge truly 
and folidly, without any previous experiment of 
things, which have never fallen under the cogni- 
zance of our fenfes. ‘To this purpofe, is what 
Ariftotle fays in the tenth chapter of his third 
book concerning the generation of infects. “* We 
« muft truft our reafon, if what it demonftrates 
“< be found to agree with the informations of 
“ our fenfes.” : 
All things therefore duly confidered, it does 
not feem unreafonable to determine, that if we 
had clear and diftint ideas of the ftructure of 
the human body, the motions of its juices, and 
every thing elfe relating to that wonderful fabrick; 
not only we fhould be able, by making a pro- 
per ufe of .fuch ideas, to mend it when impair- 
ed, but might even fo far go beyond the bounds 
of nature, as to reftore its health and vigour, 
when entirely loft and decayed. For our in- 
duftry fucceeds the better, in producing things 
the more clearly and diftinétly it comprehends 
them ; whilftignorance, on the other hand, is 
_attended with a proportionable degree of weak-. 
nefs. 
But as it is not always in our power to make 
- accurate experiments or obfervations, fo neither 
are fuch experiments always fufficient to give us 
clear and diftinét notions of the things theméelves. 
Such, for example, as on account of their ex- 
treme minutene({s or remotenefs, elude the fharp- 
nefs of our fight. Let therefore no one be 
childith enough to perfuade himfelf, that we can, 
by the bare efforts of our reafon, ever thoroughly 
underftand the genuine cauf:s of fuch things ; 
not to fay the true effects produced by them. 
For the higheft degree of wifdom we are 
capable of attaining, does not confift, as I ob- 
ferved before, in the knowledge of caufes, but 
The » By On Ope tap NA a UL Bet on 
only in the clear and diftin: comprehenfien of 
the true appearances or effects, by which fuch 
caufes difcover themfelves to our fenfes ; but 
we afterwards make ufe of thefe effects, as fo 
many fteps by which we may climb to the firtt 
caufes, and by the juft notions we thus ac- 
quire, we are enabled to produce an infinite 
number of things requifite to make life eafy 
and happy. Nay, even this knowledge reaches 
no higher than the perception of thefe effects, 
as they are made known to us by a circum- 
{pect ufe of our fenfes. And therefore, all 
our reafonings that are drawn from experi- 
ments already made in one cafe, and then ap- 
plied to another, in which we have not as yet 
made any, are to be held as dubious and 
fufpectible till they end in, and are confirmed 
by immediate experiment. 
For this reafon I am greatly pleafed with 
the illuftrious Harvey, when in the preface to 
his treatife on the generation of animals, he 
{peaks of the methods of finding truth, in the 
following words: ‘ The prefent method 
“‘ therefore, of inveftigating truth, is alto- 
‘“* gether erroneous and childith, whilf the 
“« generality are taken up in inquiring not what 
“ things are, but what others fay of them, and 
*¢ then drawing an univerfal conclufion from 
‘“* fingular premifes, to which they often af- 
* terwards add analogical reafonings, and al- 
*< moft always palm upon us for true, things 
«* that are feldom more than at the utmoft 
‘“* probable. Hence it is, that many fophifts, 
“‘ after ranfacking the inventions of others, 
** prefent them to us as their own, though 
“‘ they have done no more than change the 
“© original author’s order and words, and made, 
“‘ perhaps, fome few inconfiderable additions ; 
«‘ by thefe means they render philofophy, 
“‘ which ought to be certain and perfpicuous, 
“ dark, intricate, and confufed. For thofe, 
“ who whilft they read an author’s words, do 
“ not abftract the images of things, compre~ 
«¢ hended in their words from their proper 
“< fenfes, inftead of furnifhing their minds 
‘¢ with true ideas, fill them with falfe idols 
«* and empty fancies, which they work up in 
‘* their imagination, into fhadows and chime- 
‘ras; fo that all their fine theories or con- 
“ templations which they dignify with the 
‘© name of knowledge or fcience, ought ra- 
‘¢ ther to be confidered as the dreams of men 
“© awake, or the ravings of lunaticks.” And 
a little before, he fays, “‘ For the images of 
‘‘ things that come under the cognizance of 
‘¢ our fenfes, remain when the things them- 
«< felves have difappeared ; and thefe images 
«© conftitute memory, which, by taking in a 
‘© great number of objects, forms in its turn, 
“© what we call experience; and from expe- 
“ rience we derive univerfal reafon, definitions, 
< and maxims, or common axioms, which 
*¢ are the certain principles of knowledge.” 
He again fpeaks to the fame purpofe in his 
forty-fourth exercitation, and in the following 
terms. ‘* It.is therefore, no fuch wonder, 
« that fo many errors fhould have defcended 
even 
