1. Extent of our knowledge. Knowledge, as has been said, lying in the perception of the agreement
or disagreement of any of our ideas, it follows from hence That,
It extends no further than we have ideas. First, we can have knowledge no further than we have
ideas.
2. It extends no further than we can perceive their agreement or disagreement. Secondly, That we
can have no knowledge further than we can have perception of that agreement or disagreement.
Which perception being: 1. Either by intuition, or the immediate comparing any two ideas; or, 2. By
reason, examining the agreement or disagreement of two ideas, by the intervention of some others;
or, 3. By sensation, perceiving the existence of particular things: hence it also follows:
3. Intuitive knowledge extends itself not to all the relations of all our ideas. Thirdly, That we cannot
have an intuitive knowledge that shall extend itself to all our ideas, and all that we would know about
them; because we cannot examine and perceive all the relations they have one to another, by juxta-
position, or an immediate comparison one with another. Thus, having the ideas of an obtuse and an
acute angled triangle, both drawn from equal bases, and between parallels, I can, by intuitive
knowledge, perceive the one not to be the other, but cannot that way know whether they be equal or
no; because their agreement or disagreement in equality can never be perceived by an immediate
comparing them: the difference of figure makes their parts incapable of an exact immediate
application; and therefore there is need of some intervening qualities to measure them by, which is
demonstration, or rational knowledge.
4. Nor does demonstrative knowledge. Fourthly, It follows, also, from what is above observed, that
our rational knowledge cannot reach to the whole extent of our ideas: because between two
different ideas we would examine, we cannot always find such mediums as we can connect one to
another with an intuitive knowledge in all the parts of the deduction; and wherever that fails, we
come short of knowledge and demonstration.
5. Sensitive knowledge narrower than either. Fifthly, Sensitive knowledge reaching no further than
the existence of things actually present to our senses, is yet much narrower than either of the
former.
6. Our knowledge, therefore, narrower than our ideas. Sixthly, From all which it is evident, that the
extent of our knowledge comes not only short of the reality of things, but even of the extent of our
own ideas. Though our knowledge be limited to our ideas, and cannot exceed them either in extent
or perfection; and though these be very narrow bounds, in respect of the extent of All-being, and far
short of what we may justly imagine to be in some even created understandings, not tied down to
the dull and narrow information that is to be received from some few, and not very acute, ways of
perception, such as are our senses; yet it would be well with us if our knowledge were but as large
as our ideas, and there were not many doubts and inquiries concerning the ideas we have, whereof
we are not, nor I believe ever shall be in this world resolved. Nevertheless I do not question but that
human knowledge, under the present circumstances of our beings and constitutions, may be carried
much further than it has hitherto been, if men would sincerely, and with freedom of mind, employ all
that industry and labour of thought, in improving the means of discovering truth, which they do for
the colouring or support of falsehood, to maintain a system, interest, or party they are once engaged
in. But yet after all, I think I may, without injury to human perfection, be confident, that our
knowledge would never reach to all we might desire to know concerning those ideas we have; nor
be able to surmount all the difficulties, and resolve all the questions that might arise concerning any
of them. We have the ideas of a square, a circle, and equality; and yet, perhaps, shall never be able
to find a circle equal to a square, and certainly know that it is so. We have the ideas of matter and
thinking, but possibly shall never be able to know whether any mere material being thinks or no; it
being impossible for us, by the contemplation of our own ideas, without revelation, to discover
whether Omnipotency has not given to some systems of matter, fitly disposed, a power to perceive
and think, or else joined and fixed to matter, so disposed, a thinking immaterial substance: it being,
in respect of our notions, not much more remote from our comprehension to conceive that GOD
can, if he pleases, superadd to matter a faculty of thinking, than that he should superadd to it
another substance with a faculty of thinking; since we know not wherein thinking consists, nor to
what sort of substances the Almighty has been pleased to give that power, which cannot be in any
created being, but merely by the good pleasure and bounty of the Creator.
Whether Matter may not be made by God to think is more than man can know. For I see no
contradiction in it, that the first Eternal thinking Being, or Omnipotent Spirit, should, if he pleased,
give to certain systems of created senseless matter, put together as he thinks fit, some degrees of
sense, perception, and thought: though, as I think I have proved, Bk. iv. ch. 10, SS 14, etc., it is no
less than a contradiction to suppose matter (which is evidently in its own nature void of sense and
thought) should be that Eternal first-thinking Being. What certainty of knowledge can any one have,
that some perceptions, such as, v.g., pleasure and pain, should not be in some bodies themselves,
after a certain manner modified and moved, as well as that they should be in an immaterial
substance, upon the motion of the parts of body: Body, as far as we can conceive, being able only
to strike and affect body, and motion, according to the utmost reach of our ideas, being able to
produce nothing but motion; so that when we allow it to produce pleasure or pain, or the idea of a
colour or sound, we are fain to quit our reason, go beyond our ideas, and attribute it wholly to the
good pleasure of our Maker. For, since we must allow He has annexed effects to motion which we
can no way conceive motion able to produce, what reason have we to conclude that He could not
order them as well to be produced in a subject we cannot conceive capable of them, as well as in a
subject we cannot conceive the motion of matter can any way operate upon? I say not this, that I
would any way lessen the belief of the soul's immateriality: I am not here speaking of probability, but
knowledge; and I think not only that it becomes the modesty of philosophy not to pronounce
magisterially, where we want that evidence that can produce knowledge; but also, that it is of use to
us to discern how far our knowledge does reach; for the state we are at present in, not being that of
vision, we must in many things content ourselves with faith and probability: and in the present
question, about the Immateriality of the Soul, if our faculties cannot arrive at demonstrative certainty,
we need not think it strange. All the great ends of morality and religion are well enough secured,
without philosophical proofs of the soul's immateriality; since it is evident, that he who made us at
the beginning to subsist here, sensible intelligent beings, and for several years continued us in such
a state, can and will restore us to the like state of sensibility in another world, and make us capable
there to receive the retribution he has designed to men, according to their doings in this life. And
therefore it is not of such mighty necessity to determine one way or the other, as some, over-
zealous for or against the immateriality of the soul, have been forward to make the world believe.
Who, either on the one side, indulging too much their thoughts immersed altogether in matter, can
allow no existence to what is not material: or who, on the other side, finding not cogitation within the
natural powers of matter, examined over and over again by the utmost intention of mind, have the
confidence to conclude--That Omnipotency itself cannot give perception and thought to a substance
which has the modification of solidity. He that considers how hardly sensation is, in our thoughts,
reconcilable to extended matter; or existence to anything that has no extension at all, will confess
that he is very far from certainly knowing what his soul is. It is a point which seems to me to be put
out of the reach of our knowledge: and he who will give himself leave to consider freely, and look
into the dark and intricate part of each hypothesis, will scarce find his reason able to determine him
fixedly for or against the soul's materiality. Since, on which side soever he views it, either as an
unextended substance, or as a thinking extended matter, the difficulty to conceive either will, whilst
either alone is in his thoughts, still drive him to the contrary side. An unfair way which some men
take with themselves: who, because of the inconceivableness of something they find in one, throw
themselves violently into the contrary hypothesis, though altogether as unintelligible to an unbiassed
understanding. This serves not only to show the weakness and the scantiness of our knowledge, but
the insignificant triumph of such sort of arguments; which, drawn from our own views, may satisfy us
that we can find no certainty on one side of the question: but do not at all thereby help us to truth by
running into the opposite opinion; which, on examination, will be found clogged with equal
difficulties. For what safety, what advantage to any one is it, for the avoiding the seeming
absurdities, and to him unsurmountable rubs, he meets with in one opinion, to take refuge in the
contrary, which is built on something altogether as inexplicable, and as far remote from his
comprehension? It is past controversy, that we have in us something that thinks; our very doubts
about what it is, confirm the certainty of its being, though we must content ourselves in the
ignorance of what kind of being it is: and it is in vain to go about to be sceptical in this, as it is
unreasonable in most other cases to be positive against the being of anything, because we cannot
comprehend its nature. For I would fain know what substance exists, that has not something in it
which manifestly baffles our understandings. Other spirits, who see and know the nature and inward
constitution of things, how much must they exceed us in knowledge? To which, if we add larger
comprehension, which enables them at one glance to see the connexion and agreement of very
many ideas, and readily supplies to them the intermediate proofs, which we by single and slow
steps, and long poring in the dark, hardly at last find out, and are often ready to forget one before we
have hunted out another; we may guess at some part of the happiness of superior ranks of spirits,
who have a quicker and more penetrating sight, as well as a larger field of knowledge.
But to return to the argument in hand: our knowledge, I say, is not only limited to the paucity and
imperfections of the ideas we have, and which we employ it about, but even comes short of that too:
but how far it reaches, let us now inquire.
7. How far our knowledge reaches. The affirmations or negations we make concerning the ideas we
have, may, as I have before intimated in general, be reduced to these four sorts, viz., identity, co-
existence, relation, and real existence. I shall examine how far our knowledge extends in each of
these:
8. Our knowledge of identity and diversity in ideas extends as far as our ideas themselves. First, as
to identity and diversity. In this way of agreement or disagreement of our ideas, our intuitive
knowledge is as far extended as our ideas themselves: and there can be no idea in the mind, which
it does not, presently, by an intuitive knowledge, perceive to be what it is, and to be different from
any other.
9. Of their co-existence, extends only a very little way. Secondly, as to the second sort, which is the
agreement or disagreement of our ideas in co-existence, in this our knowledge is very short; though
in this consists the greatest and most material part of our knowledge concerning substances. For
our ideas of the species of substances being, as I have showed, nothing but certain collections of
simple ideas united in one subject, and so co-existing together; v.g. our idea of flame is a body hot,
luminous, and moving upward; of gold, a body heavy to a certain degree, yellow, malleable, and
fusible: for these, or some such complex ideas as these, in men's minds, do these two names of the
different substances, flame and gold, stand for. When we would know anything further concerning
these, or any other sort of substances, what do we inquire, but what other qualities or powers these
substances have or have not? Which is nothing else but to know what other simple ideas do, or do
not co-exist with those that make up that complex idea?
10. Because the connexion between simple ideas in substances is for the most part unknown. This,
how weighty and considerable a part soever of human science, is yet very narrow, and scarce any
at all. The reason whereof is, that the simple ideas whereof our complex ideas of substances are
made up are, for the most part, such as carry with them, in their own nature, no visible necessary
connexion or inconsistency with any other simple ideas, whose co-existence with them we would
inform ourselves about.
11. Especially of the secondary qualities of bodies. The ideas that our complex ones of substances
are made up of, and about which our knowledge concerning substances is most employed, are
those of their secondary qualities; which depending all (as has been shown) upon the primary
qualities of their minute and insensible parts; or, if not upon them, upon something yet more remote
from our comprehension; it is impossible we should know which have a necessary union or
inconsistency one with another. For, not knowing the root they spring from, not knowing what size,
figure, and texture of parts they are, on which depend, and from which result those qualities which
make our complex idea of gold, it is impossible we should know what other qualities result from, or
are incompatible with, the same constitution of the insensible parts of gold; and so consequently
must always co-exist with that complex idea we have of it, or else are inconsistent with it.
12. Because necessary connexion between any secondary and the primary qualities is
undiscoverable by us. Besides this ignorance of the primary qualities of the insensible parts of
bodies, on which depend all their secondary qualities, there is yet another and more incurable part
of ignorance, which sets us more remote from a certain knowledge of the co-existence or inco-
existence (if I may so say) of different ideas in the same subject; and that is, that there is no
discoverable connexion between any secondary quality and those primary qualities which it
depends on.
13. We have no perfect knowledge of their primary qualities. That the size, figure, and motion of one
body should cause a change in the size, figure, and motion of another body, is not beyond our
conception; the separation of the parts of one body upon the intrusion of another; and the change
from rest to motion upon impulse; these and the like seem to have some connexion one with
another. And if we knew these primary qualities of bodies, we might have reason to hope we might
be able to know a great deal more of these operations of them one upon another: but our minds not
being able to discover any connexion betwixt these primary qualities of bodies and the sensations
that are produced in us by them, we can never be able to establish certain and undoubted rules of
the consequence or co-existence of any secondary qualities, though we could discover the size,
figure, or motion of those invisible parts which immediately produce them. We are so far from
knowing what figure, size, or motion of parts produce a yellow colour, a sweet taste, or a sharp
sound, that we can by no means conceive how any size, figure, or motion of any particles, can
possibly produce in us the idea of any colour, taste, or sound whatsoever: there is no conceivable
connexion between the one and the other.
14. And seek in vain for certain and universal knowledge of unperceived qualities in substances. In
vain, therefore, shall we endeavour to discover by our ideas (the only true way of certain and
universal knowledge) what other ideas are to be found constantly joined with that of our complex
idea of any substance: since we neither know the real constitution of the minute parts on which their
qualities do depend; nor, did we know them, could we discover any necessary connexion between
them and any of the secondary qualities: which is necessary to be done before we can certainly
know their necessary co-existence. So, that, let our complex idea of any species of substances be
what it will, we can hardly, from the simple ideas contained in it, certainly determine the necessary
co-existence of any other quality whatsoever. Our knowledge in all these inquiries reaches very little
further than our experience. Indeed some few of the primary qualities have a necessary
dependence and visible connexion one with another, as figure necessarily supposes extension;
receiving or communicating motion by impulse, supposes solidity. But though these, and perhaps
some others of our ideas have: yet there are so few of them that have a visible connexion one with
another, that we can by intuition or demonstration discover the co-existence of very few of the
qualities that are to be found united in substances: and we are left only to the assistance of our
senses to make known to us what qualities they contain. For of all the qualities that are co-existent
in any subject, without this dependence and evident connexion of their ideas one with another, we
cannot know certainly any two to co-exist, any further than experience, by our senses, informs us.
Thus, though we see the yellow colour, and, upon trial, find the weight, malleableness, fusibility, and
fixedness that are united in a piece of gold, yet; because no one of these ideas has any evident
dependence or necessary connexion with the other, we cannot certainly know that where any four of
these are, the fifth will be there also, how highly probable soever it may be; because the highest
probability amounts not to certainty, without which there can be no true knowledge. For this co-
existence can be no further known than it is perceived; and it cannot be perceived but either in
particular subjects, by the observation of our senses, or, in general, by the necessary connexion of
the ideas themselves.
15. Of repugnancy to co-exist, our knowledge is larger. As to the incompatibility or repugnancy to
coexistence, we may know that any subject may have of each sort of primary qualities but one
particular at once: v.g. each particular extension, figure, number of parts, motion, excludes all other
of each kind. The like also is certain of all sensible ideas peculiar to each sense; for whatever of
each kind is present in any subject, excludes all other of that sort: v.g. no one subject can have two
smells or two colours at the same time. To this, perhaps will be said, Has not an opal, or the infusion
of lignum nephriticum, two colours at the same time? To which I answer, that these bodies, to eyes
differently placed, may at the same time afford different colours: but I take liberty also to say, to eyes
differently placed, it is different parts of the object that reflect the particles of light: and therefore it is
not the same part of the object, and so not the very same subject, which at the same time appears
both yellow and azure. For, it is as impossible that the very same particle of any body should at the
same time differently modify or reflect the rays of light, as that it should have two different figures
and textures at the same time.
16. Our knowledge of the co-existence of powers in bodies extends but a very little way. But as to
the powers of substances to change the sensible qualities of other bodies, which make a great part
of our inquiries about them, and is no inconsiderable branch of our knowledge; I doubt as to these,
whether our knowledge reaches much further than our experience; or whether we can come to the
discovery of most of these powers, and be certain that they are in any subject, by the connexion with
any of those ideas which to us make its essence. Because the active and passive powers of bodies,
and their ways of operating, consisting in a texture and motion of parts which we cannot by any
means come to discover; it is but in very few cases we can be able to perceive their dependence on,
or repugnance to, any of those ideas which make our complex one of that sort of things. I have here
instanced in the corpuscularian hypothesis, as that which is thought to go furthest in an intelligible
explication of those qualities of bodies; and I fear the weakness of human understanding is scarce
able to substitute another, which will afford us a fuller and clearer discovery of the necessary
connexion and coexistence of the powers which are to be observed united in several sorts of them.
This at least is certain, that, whichever hypothesis be clearest and truest, (for of that it is not my
business to determine,) our knowledge concerning corporeal substances will be very little advanced
by any of them, till we are made to see what qualities and powers of bodies have a necessary
connexion or repugnancy one with another; which in the present state of philosophy I think we know
but to a very small degree: and I doubt whether, with those faculties we have, we shall ever be able
to carry our general knowledge (I say not particular experience) in this part much further. Experience
is that which in this part we must depend on. And it were to be wished that it were more improved.
We find the advantages some men's generous pains have this way brought to the stock of natural
knowledge. And if others, especially the philosophers by fire, who pretend to it, had been so wary in
their observations, and sincere in their reports as those who call themselves philosophers ought to
have been, our acquaintance with the bodies here about us, and our insight into their powers and
operations had been yet much greater.
17. Of the powers that co-exist in spirits yet narrower. If we are at a loss in respect of the powers
and operations of bodies, I think it is easy to conclude we are much more in the dark in reference to
spirits; whereof we naturally have no ideas but what we draw from that of our own, by reflecting on
the operations of our own souls within us, as far as they can come within our observation. But how
inconsiderable a rank the spirits that inhabit our bodies hold amongst those various and possibly
innumerable kinds of nobler beings; and how far short they come of the endowments and
perfections of cherubim and seraphim, and infinite sorts of spirits above us, is what by a transient
hint in another place I have offered to my reader's consideration.
18. Of relations between abstracted ideas it is not easy to say how far our knowledge extends.
Thirdly, As to the third sort of our knowledge, viz., the agreement or disagreement of any of our
ideas in any other relation: this, as it is the largest field of our knowledge, so it is hard to determine
how far it may extend: because the advances that are made in this part of knowledge, depending on
our sagacity in finding intermediate ideas, that may show the relations and habitudes of ideas
whose co-existence is not considered, it is a hard matter to tell when we are at an end of such
discoveries; and when reason has all the helps it is capable of, for the finding of proofs or examining
the agreement or disagreement of remote ideas. They that are ignorant of Algebra cannot imagine
the wonders in this kind are to be done by it: and what further improvements and helps
advantageous to other parts of knowledge the sagacious mind of man may yet find out, it is not easy
to determine. This at least I believe, that the ideas of quantity are not those alone that are capable of
demonstration and knowledge; and that other, and perhaps more useful, parts of contemplation,
would afford us certainty, if vices, passions, and domineering interest did not oppose or menace
such endeavours.
Morality capable of demonstration. The idea of a supreme Being, infinite in power, goodness, and
wisdom, whose workmanship we are, and on whom we depend; and the idea of ourselves, as
understanding, rational creatures, being such as are clear in us, would, I suppose, if duly considered
and pursued, afford such foundations of our duty and rules of action as might place morality
amongst the sciences capable of demonstration: wherein I doubt not but from self-evident
propositions, by necessary consequences, as incontestible as those in mathematics, the measures
of right and wrong might be made out, to any one that will apply himself with the same indifferency
and attention to the one as he does to the other of these sciences. The relation of other modes m