LOGIC, 7 
ivhat we can know, what we may wifh to know, or what 
we ought to know. 
As'to the theoretically or logically determined horizon, 
in particular, we may confider it, either in an objective or 
a fubjeClive point of view. 
Confidered Objectively, the Horizon is either hijlorical or 
, rational, The former is much more extenfive than the 
latter; indeed our hiftorical Knowledge has no bounds. 
The rational horizon, on the other hand, may be fixed, 
fince, for example, it may be determined to what kind of 
objects mathematical knowledge cannot extend; and alio 
how farreafon can proceed a priori in philofophical know¬ 
ledge independently of experience. 
Confidered Subjectively, the horizon is either univerfal 
and abfolute, or particular and conditional. (Private 
Horizon.) 
By the abfolute and univerfal horizon is to be under- 
ftood the congruence of the bounds of human Knowledge 
with thofe of human Perfeftion. And here the queftion 
arifes, What can man know ? 
The determination of the Private Horizon depends upon 
a variety of empirical conditions and peculiar views; for 
inftance, upon the age, the fex, the Ration, mode of life, 
See. Each clafs of men has, therefore, according to its 
particular ends and views, and the peculiar powers of 
knowledge it poffefles, a particular horizon. Each Mind, 
in proportion to its individual powers and views, has an 
horizon proper to itfelf. Laftly, we may conceive the 
idea of an horizon of Common Senfe as diftinguifhed from 
the horizon of Science, the latter of which requires princi¬ 
ples to determine what can and what cannot be known. 
What cannot be known is above our horizon, what need 
not be known is out of our horizon. The latter however 
muft be underftood relatively, that is, as referring merely 
to particular private aims, to the attainment of which 
fome fpecies of Knowledge may not only contribute no¬ 
thing, but actually prove detrimental. For there is no 
knowledge that is abfolutely and in all refpefts ufelefs, 
though its utility may not always be apparent. Hence the 
reproach call: by fuperficial minds upon thofe great men 
who labour to cultivate the Sciences, in the queftion, Of 
what ufe is this ? is as unwife as it is unjuft. He who re- 
folves to engage in the fciences muft never for a moment 
propofe this queftion to himfelf. If a fcience explains 
but one, even poftible objeft, it is on that account alone 
fufficiently ufeful. All logically-perfeft knowledge has 
always fome pofiible ufe, which, though unknown to 
us, may perhaps be dilcovered by pofterity. Had man 
in the culture of Science always attended to imme¬ 
diate advantage and utility, we fhould have had neither 
Arithmetic nor Geometry ; but our underftanding is fo 
conftituted, that it takes a greater delight in mere intro- 
fpeftion than in all the advantage that can accrue from 
it. This Plato long ago obferved. Man is here con- 
feious of his pre-eminence; he feels what is meant by 
having underftanding. Thofe who are not fenfible of 
this may envy the beafts. The external value of Know¬ 
ledge in its mere application muft not be put in compari- 
fon with the internal worth which it pofleffes in its lo¬ 
gical perfeftion. 
In the extenfion and demarcation of our knowledge, 
the following rules may be ufeful. 
x. To determine our own horizon at an early age, but not 
until we are able to fix it for oufelves, which leldom occurs 
before the age of twenty. 
2. Not too frequently, nor for flight reafons, to change 
our horizon. 
3. Not to meafure the horizon of others by our own, 
nor to confider that as ufelefs which is fo merely to our- 
felves; it being rafh to attempt to fix the horizon of 
others, fince we are feldom fufficiently acquainted either 
with their views or capacities. 
4.. Neither too much to extend nor to contraft our ho¬ 
rizon. For he who feeks to know too much, in the end 
knows nothing; and on the coutrary, be who believes 
that certain things do not concern him may poffibTy de¬ 
ceive himfelf; as for inftance, the philofopher who fhould 
believe that hiftory is of no ufe to him. 
5. To endeavour, previoufly, to determine the abfolute 
horizon of the whole human race. 
6. To determine the place which the fcience we have 
principally in view holds in the horizon of colleftive 
knowdedge. Here the univerfal Encyclopaedia may ferve 
as a general Map of the Sciences. 
7. Before we determine our own particular horizon, to 
examine carefully for what fort of knowledge we have the 
greateft capacity and inclination ; to confider what may 
be more or lefs ferviceable to our particular duties, and 
what may be incompatible with duties which are abfo¬ 
lutely neceffary. 
8. And laftly, to endeavour at all times to extend our 
horizon rather than to contraft it. 
With refpeft to the extenfion of knowledge generally, 
we need not dread that we {hall proceed too far in the 
purfuit of it; for nature has fufficiently circumfcribed 
us. The Criticifm of Reafon, of Hiftory, and a general 
fpirit direfted to knowledge in the great, and not merely 
in the detail, will always contraft its circumference without 
diminifhing its contents. Thus is it cleared from the 
hufk which is no longer neceffary. In the progrefs of Na¬ 
tural Hiftory, of the Mathematics, See. new and fliorter me¬ 
thods will conftantly be invented to reduce the multiplicity 
of books. Thus every thing will be more eafily attained 
and with lefs burthen to the memory. He therefore who 
fhould difeover the means of comprefling Hiftory within 
a few permanent Ideas would have the merit of a genius. 
Ignorance is oppofed to the logical perfeftion of know¬ 
ledge merely with refpeft to its extent. This negative 
imperfeftion is, on account of the limited nature of the 
Underftanding, infeparable from all human Knowledge. 
Ignorance may be confidered either in an objective or 
fubjeCiive point of view. 
1. Objectively. Ignorance is either material or for¬ 
mal. The former confifts in a want of Hiftorical 
Knowledge, the latter in a want of Rational Knowledge. 
We ought not, in any department, to be entirely igno¬ 
rant. But we may indeed limit our hiftorical knowledge, 
the better to cultivate rational knowledge; and vice verfd. 
2. Subjectively. Ignorance is either learned, feientfe, 
or common. Whoever clearly perceives the bounds of know¬ 
ledge, confequently where the field of ignorance begins ; 
for inftance, the philofopher who proves how little we can 
know of the nature of gold, for want of the neceffary 
data ; is learnedly ignorant. He, on the contrary, who 
is ignorant without perceiving the grounds of his igno¬ 
rance, is vulgarly ignorant. Such a man does not even 
know that he is ignorant; for, to reprefent his ignorance 
to himfelf, he would require the aid of fcience. As a 
blind man can form no idea of darknefs until he has feen 
the light. 
The knowledge of our ignorance, therefore, prefuppofes 
fcience, and renders usmodeft; while an imaginary know¬ 
ledge inflates. Thus the ignorance of Socrates was glo¬ 
rious, becaufe, according to his own confeflion, it was 
properly a knowledge of his ignorance. 
To be ignorant of thofe things which rife above our 
horizon is irreproachable, and may be allowed, though 
only in a relative fenfe, with refpeft to the fpeculative 
ufe of our knowing faculty, in as much as the objefts 
are here, though not above, yet out of, our horizon. Ig¬ 
norance is, however, difgraceful in fuch things as are ef- 
fential, and at the fame time eafy to be known. 
There is a difference between not knowing and not no¬ 
ticing a thing. It is advantageous to pafs over many 
things that would be detrimental to our knowledge, 
Abftraftion differs from both. We abffraft from our 
knowledge when we confider it in the general^ as a Prin¬ 
ciple. To abftraft thus from all that is foreign to our 
objeft, is extremely ufeful. 
Thofe who cultivate their reafon moft, are commonly 
a deJideatg. 
4 . 
