‘etre “3 We © RO. Gott me Tt oe eet cea S. 
fingle infect, that may not be referred to one of 
the four orders of mutations which Ihave propof- 
ed; for to me, if I may here truft my reaton, the 
thing appears impoffible. I leave it to time to dif- 
cover the truth of this affertion ; and do not de- 
fire any credit to be given to my relations, unlefs 
the things I {peak are found to agree exactly 
with the originals, as I have defcribed them after 
nature with all the exactnefs and perfpicuity I 
was mafter of. 
- Having thus produced every thing, which in 
my opinion could be faid in general, or in par- 
ticular, concerning infects, I had refolved to add 
another differtation on their eggs, worms, and 
Nymphs: but I muft defer this to fome- other 
opportunity, I had even flattered myfelf with 
the hopes of being able to prefent the public 
with a feparate account of the little infects found 
in the bodies of others of a larger fize ; but as 
yet I want fufficient experiments for that pur- 
pofe, though I am firmly perfuaded that no- 
thing is to be attributed to chance in the gene- 
ration of them. 
I fhall now fay no more on this fubject, as it 
is moft evident that all God’s works are go- 
verned by the fame rules; and as the true and 
primitive origins of them are infinitely beyond 
the reach of our comprehenfion, fo that we can- 
not be faid to know more than the bare outlines 
of that infinite Being’s image, to whom they 
owe their exiftence; fo I may hence, for certain, 
conclude, that all the knowledge and wifdom of 
philofophers, confifts merely in an accurate per- 
ception of thefe elegant appearances or effects, 
which are produced by firft caufes, and are 
often themfelves, in their turn, the caufes of 
other effects. For this reafon, we fhould ftre- 
nuoufly endeavour to make ourfelves well ac- . 
quainted with thefe appearances, and then draw 
from them firm rules and principles; otherwife, 
as I have hinted in my preface, we may eafily 
lofe our way, and ftray into the paths of error, 
as difputing on nature, which is quite inexhauft- 
ible, without {ufficient experiments, which, on 
fuch an occafion, are as neceffary to find us a 
path, confidering with what darknefs of igno- 
rance we are furrounded, as a ftaff is to the 
blind. It often happens, through our own fault, 
that thofe things, of which we might acquire 
competent notions with very little trouble, be- 
come not only dark, but quite incomprehenfible 
to us, fo as to encreafe our blindnefs, by the er- 
roneous inferences we draw from them, rather 
than add to our knowledge. Of this our great 
weaknefs, Goedaert alone is a fufficient example ; 
for that author, by falfely imagining to himfelf, 
for want of proper experiments, that Caterpil- 
lars, degenerated into crippled and imperfect in- 
fects, as often as they performed their mutations, 
without being properly grown and fed for that 
purpofe, not only in confequence of this falfe 
pofition, involved all his other experiments in 
the moft perfect darknefs, but contraGed himfelf 
fuch a blindnefs, that he could not perceive one 
of the moft excellent principles of natural hifto- 
ty, though it lay directly under his eyes. I omit 
naining many other naturalifts, who, too lazy, 
135 
A 
or too proud, to thake experimeiits, and gnided 
only by their week reafon, or weaker imagina- 
tion, have argued on the mutations of infects, 
with juft as much propriety, as a blind man may 
be {uppofed to fpeak of colours; infomuch that I 
fhould Be afhamed to put my readers in mind 
of their empty and childifh reafonings. Nor is 
there the leaft thadow of excufe, for the unwar- 
rantable boldnefs of fuch perfons, who were not 
afhamed to fpeak without any hefitation or doubt 
of things, whofe catifes and principles they were 
utterly unacquainted with. But, to fpeak my 
mind with freedom and candour: if we are to 
regard as idle and vain, all thofe reafonings of 
ours, which cannot be primarily demonftrated 
by experiments, and do not ultimately terminate 
in them, no reafonings can be fo ftrong and 
certain, as thofe which are drawn from the very 
obfervations and experiments, in which they 
may likewife be found to terminate. All fuch 
arguments, therefore, as want this frm and im- 
moveable bafis of experiments, are to be greatly 
fufpected of error, whatever fyllogifms and enu- 
merations people may think proper to build them 
upon; and when they do not exactly agree with 
experiments, they deferve to be rejected. Of 
‘this opinion was likewife the illuftrious Des Car- 
tes, who, in his eflay upon method, has the fol- 
lowing words. ‘* For I was always of opinion, 
* that more truth is to be found in thofe reafon- 
ings, which men make ufe of in the com- 
mon affairs of life, whofe bad fuccefs may 
prove a kind of punifhment for their reafon- 
ing ill, than in thofe which fome idle doétor, 
cooped up in his ftudy, has invented concern- 
ing this entia rationis, and fuch other empty 
queftions, that conduce nothing to the eafe and 
happinefs of life, and from which he expeds 
no other advantage, uniefs that of reaping fo 
much the greater harveft of empty glory from 
his afguments; as they contain lefs of truth 
and common fenfe, on account of the extra- 
ordinary ftrength of genius, and application 
requifite to give an impofing air to fuch ab- 
furdities.’” 
If we duly confider the words of this able phi- 
lofopher, and the great weight and importance 
of experiments, I believe we thal] fnd it not un- 
juft to dignify with the name of reafon that 
faculty of our minds, by the affiftance of which, 
we form clear and diftiné notions of things, 
whilft we make proper ufe of our fenfes in {uffi- 
«Client experiments, fo as to be able afterwards to 
effect exact copies of the originals we have thus 
endeavoured to be thoroughly acquainted with. 
For this reafon it is; that our idea of any thing 
is fatd to be more or lefs clear and diftinét, ac- 
cording as we can produce another thing more or 
lefs like it; and are therefore faid to have more or 
lefs the power of it. This being granted, it 
fhould follow, that we have no clear; difting, 
or perfect knowledge of any things, except of 
fuch as we can truly and effectually produce, ac- 
cording to the notions we have of them: {fo that 
folid and perfect knowledge muft be allowed to 
be a very uncommon thing in man, and to be 
confined within very narrow bounds. This is an 
3 im- 
ce 
