L O 
Negative marks ferve to guard us again# error: they are 
therefore unneceflary in thole cafes where error is impof- 
fible, and only necefTary and important when they guard 
us again# an important error into which we might ealily 
have fallen. Thus for example, with refpeft to a being 
fuch as God, negative marks are of the utmoft importance. 
By affirmative marks our objeft is to underfund a thing. 
By negative, into which all marks whatfoever may be con¬ 
verted, our aim is not to mifunderftand, or not to err, 
though we Ihould even, learn nothing of a thing. 
4. Important and prolific, or barren and un¬ 
important, marks. A mark is important and prolific 
when it is a ground of knowledge which has very nu¬ 
merous confequences; either with refpeft to its internal life, 
that is in derivation, where it enables us to know a great 
deal of the thing itfelf; or with refpeft to its external ufe, 
in comparifcn, where it ferves to point out the agreement 
and difference of things. 
We mull: however diltinguifh here the Logical impor¬ 
tance and fruitfulnefs from the Practical, that is, the 
Utility. 
5. Sufficient and necessary, and insufficient and 
accidental, marks. A mark is fufjicient when it ferves 
to diftinguifh the thing from all others. If it does not 
do this, it is injufficient ; for inftance, Barking as the mark 
of a dog. The iufficiency as well as the importance of 
marks is only to be underitood relatively, with refpeft to 
the ends we have in view in our-knowledge. 
Neceffary marks are laftly thofe which mult always be 
met with in the thing reprefented ; and are alfo termed ef- 
Jential, in oppofition to the uneffiential or accidental, which 
may be feparated from the conception of the thing. 
There is (fill another diftinftion among neceffary marks. 
Some of them apply to the thing as the grounds of other 
marks in the fame thing; others only as the confequences 
of other marks, or as being derived from them. 
’The former are primitive and conftitutive marks ; that is 
to fay, thofe which are not derived from any other marks 
in the conception. • Tlie latter are attributes, which only 
apply to the thing as being derived from the primitive 
•marks in .its conception. For inlfance: the three angles 
in the conception of a triangle are derived from there be¬ 
ing three fides. 
The uneffiential or accidental marks are again twofold ; 
namely, they refer either to the internal determination, 
(modi) of a thing, or to the external relation (relationis.) 
As for example, learning is a mark that denotes an internal 
determination of man; but mafer or fcrvant an external 
relation. 
The aggregate of all the primitive marks of a thing, or 
the fufficiency of its marks according to co-ordination or 
fub or din avion, conftitutes its essence. 
But in this explanation we muff by no means think 
of the real or natural effence of things, which it is im- 
poflible ever .to difcover. Since logic abftrafts from 
the matter of all knowledge, confequently from the thing 
itfelf; it follows that this fcience can only treat of the lo¬ 
gical effence of things-, and this we can ealily obtain. For 
here nothing farther is required than a knowledge of all 
thofe predicates which determine the conception of an 
objeft. Whereas to the real effence of a thing (effie rei) is 
required the knowledge of thofe predicates on which de¬ 
pends whatever belongs to its exflence as determining 
ground. Thus, in order to determine the logical effence 
of a body, we need not leek the data in nature; but only 
attend to the marks which originally conftitute its funda¬ 
mental conception, (conflitutiva rationis.J For the logical 
effence is nothing but the primitive and fundamental con¬ 
ception of all the neceffary marks of a thing, (effie con¬ 
cepts.) 
The firft ftep requifite for perfecting our knowledge as 
to Quality is clearnefs. The fecond is a higher degree of 
clearnefs, namely diftinftnefs, which confifts in the clear¬ 
nefs of its marks. Logical diftinftnefs in general, mult be 
diltinguilhed from afthdical. The logical depends upon 
g i c. n 
the objective, the tefihelical upon the fubjeftive, clearnefs of 
marks. The former is clearnefs by conception ; the latter 
clearnefs by intuition. Ailthetical diftinftnefs confilts in 
mere livelinefs and intelligibility, that is, in a clearnefs of 
marks by examples in the concrete ; (for many things may 
he intelligible which are not diftinft, and many things 
may be diftinft which are difficult to be underitood, be- 
caufe they refer to remote marks whole connection with' 
the intuition is only pollible by a long feries.) 
Objeftive diffi.nti'nefs frequently occalions Jubjedliveobfeurity, 
and converfely. Hence logical diftinft-tiefs is frequently 
attainable only at the expenfe of afllidical ; and the latter 
is often injurious to the former, by examples and fimilies 
ill-adapted, and only ufed according to analogy. Belides, 
examples are not marks, nor do they belong as parts to 
the conception ; they are only intuitions which may af- 
fift in forming conceptions. Diftinftnefs by examples, 
that is, mere intelligibility, is quite different from dif¬ 
tinftnefs by conceptions as marks. In the union of 
ceflhetical or popular with fcholaJUc or logical diftinftnefs, con- 
FiIts the power of reprefenting abftraft and profound know¬ 
ledge in a clear manner, and adapting it to the capacity 
of common fenfe. 
Logical diftinftnefs in particular may be termed complete 
diftinftnefs ; for here all the marks taken together that con- 
Ititute the whole conception inuft be rendered diftinft. A 
conception may be completely diftinft with refpeft to the to¬ 
tality of its Co-ordinate or of its Subordinate marks. (In the 
former confifts the extenjive diftinftnefs of a conception, which 
is all'o termed its amplenefs. In the latter the intenfive diflinft- 
nefs, namely its profundity.) The extenfi ve diltiriftnels may 
alfo be termed the external completenefs, and the intenfive 
the internal completenefs, of the clearnefs of marks. This 
latter completenefs can only be obtained by Ideas of Rea- 
fon and by arbitrary conceptions of underftanding, bus 
not empirically. 
Extenfve quantity of Diftinftnefs, when it is not abundant, 
is termed Precifion. The ample and the precife taken toge¬ 
ther conftitute the adequate, (cognitionum quae rem ade- 
quat.) When the intenfwely-adequate knowledge, that is, 
the profound, is combined with the extenftvcly-adequate, that 
is, the ample and precife-, they produce, according to qua¬ 
lity, the greateft perfection of all human knowledge; 
(ccnfummata cognitionis perfectio.) 
Since it is the bufinels of Logic to render clear concep¬ 
tions diftinft, we may now enquire, how this diftinftnefs 
is produced ? 
The Diftinftnefs of knowledge may be obtained in two 
ways: firftly, by Analyfis, by which we difcover all thofe 
marks that are already thought in a given conception 5 
fecondly, by Synthcfis, where we trace all thole marks 
which are added as parts of an entire polfible conception. 
Hence there is an effential difference between forming a 
di/iincl conception, and rendering a conception diftinft. In or¬ 
der to form a diftinft conception, w»e commence from the 
parts, and proceed to the whole. At firft there are no 
marks at all; but we obtain thefe by means of fynthelis, 
and thus generate fynthetic diftinftnefs, which really extends 
the matter of the conception by that which is added to it 
as a mark from the intuition, (whether pure or empirical.) . 
The mathematician and natural philofopher both ufe this 
fynthetical procedure in forming diftinft conceptions. 
For all diftinftnefs, in what' is purely mathematical as well 
as in experimental knowledge, depends upon an extenfion 
of its conception by the fynthelis of marks. 
In order to render a conception diftinft, we begin with 
the whole, and proceed analytically to the parts, by which 
we do not in the leaft extend our knowledge. The mat¬ 
ter remains the fame, the form alone is changed ; by which 
we are enabled to diftinguifh better, or to become clearly 
confcious of that which originally lay in the given con¬ 
ception. As by colouring a map we add nothing to it;, 
but merely render its parts more diftinft ; I'o we clear 
up a conception by the analyfis of its marks, without in 
the leaft increafing its contents. By a Sjnthsfts of marks 
a. thfr. 
