208 
The former, during a long and active life, 
passed many years in his  theologico- 
metaphysico-political lucubrations, with 
which the world could well have dis- 
pensed: the latter is following his ex- 
ample, by quitting the laboratory to 
write on metaphysics and logic. I shall 
not attempt to give an abstract of a per- 
formance which, being divided into chap- 
ters, sections, and eleven or twelve hun- 
dred canons, rules, or maxims (I know 
not what to call them), necessarily con- 
tains much desultory and detached rea- 
soning. + 
I shall therefore content myself with 
copying the principal heads into, which 
the work is divided: after this I shall 
notice those passages which appear to me 
liable to censure, either for the false rea- 
soning they contain, or for any striking 
errors which may appear in them; and 
also any inelegancies or improprieties of 
‘style from which a work of this kind 
should, as muchas possible, be exempt; 
and then conclude with the more agree- 
able employment, viz. that of selecting 
observations that may be useful. 
The principal heads are as follow:— 
Of the general objects of logick; of words 
and propositions; of compound propo- 
sitions; of the properties of proposi- 
tions; of complex, modal, and identic 
propositions; of ratiocination, and its 
essential principles; of the different ef- 
fects of ratiocination; of ambiguous or 
suspicious proofs: of fallacious proofs ; 
of probable proots; of the application 
of calculation to probability; of false 
principles;) of sophisms; of technical 
modes of reasoning; of method. 
We find in the Preface (page in, &c.) 
that Locke and others have been guilty 
of an egregious mistake, by imagining 
that the true way of acquiring a habit of 
reasoning closely, is to exercise ourselves 
in mathematical demonstrations. The 
author objects to this opinion, from these 
‘considerations, (viz,) that the mode: of 
reasoning adopted by mathematicians 
-being founded on the relation of identity,. 
is not transferrable to the other sciences; 
and that being accustomed to the highest 
degree of evidence, they become insen- 
sible to any others.. To confirm this, he 
presents us with a string of many good 
mathematicians, who have proved bad lo- 
gicians. aaa 
Now, Sir, the true inference seems to 
bave escaped the author, which 1s, that 
when a man has excelled in one pursuit, 
he may be expected to fail in another: 
«¢ Non Omnia possumus omnes.” A good 
/ &, 
Remarks on Dr. Kirwan’s “ Logick.” 
* 
[April 1, 
mathematician, or a good chemist, may 
prove a bad logician, not because he is 
insensible to the proper degree of evi- 
dence required in reasoning, but because 
his time has been principally devoted to 
other pursuits. 
Legick, p. 1.—“ Logick is both a sci- 
ence and gn art;-it is a science inas- 
much as by analysing the elements,” &c. 
This is the commencement of the very 
first sentence in the work: I should haye 
supposed the word elements to have been 
inserted by: mistake; but we find the 
idea repeated (p. 212, r. 404), “ It has 
been laid down (says the author) as an 
incontrovertible trath, that water was ar 
element and that elements were [are] in- 
decomposable, yet the contrary is now 
almost generally acknowledged.” 
Can Dr. K. be ignorant of the mean- 
ing of the word element 2 Ought he not 
to know, that, though water had formerly 
been erroneously supposed an element, 
there must be first constituent principles 
in water, as well as in all other bodies— 
that those when discovered must be ele- 
ments ; and that those elements must ne- 
cessarily be indecomposable. ats 
Page 4, r. 14.—Mr. Locke says: (a 
quoted by Dr. Kirwan), that the primary 
end of words, as signs, 1s to mark the ideas 
we have of the things signified. 
Dr. Kirwan contends that the primary 
end of words, as signs, is to mark not the 
ideas of words, but the things signified 
by them. 
Is Dr. K. not aware that the only 
knowledge we have of things is by the 
means of ideas? and that therefore we 
may be said to know nothing but ideas. 
He offers the following illustration: 
“ If I say that a certain tower is round, 
which, on a nearer approach, is found to 
be angular, I should not have fallen into 
any mistake, if I meant only to convey 
my idea of it, according to Mr. Locke’s 
terminology; but as I certainly meant 
the real tower, it must be allowed I was 
mistaken.” 3 
Now, Sir, this illustration answets no 
purpose; tor though I, who saw the tower, 
and pronounced it round, may have been 
deceived, and though I, who now see it 
angular, may judge rightly in both cases, 
I pronounce only my ownideas. There- 
fore it appears to me, that Mr. Locke’s 
terminology (to use the author’s unusual 
word) is right. 
The immortal Berkeley (as Dr. K. styles 
him), to whose ideal metaphysics Dr, K, 
seems to be a convert, would surely have 
agreed in the propriety of Locke’s defi- 
: nition ; 
