nature of a substance. We have one, or both of _two_ objects in view,
the discovery of the separate bodies that co-exist in the substance,
or rather that constitute the substance, which is nothing more than
the separate bodies themselves, or the discovery of that series of
changes, of which the presence of this particular substance, in some
new relative position with respect to other bodies, forms a part; the
changes which other bodies, in consequence of this altered relative
position, occasion in _it_, with the changes which it occasions in
other bodies.
On these two different objects of physical investigation, the
co-existing elements of bodies, and their successions of changes, it
may be of advantage to dwell a little more fully in elucidation of
the method which we have to pursue in our own department of physical
research; for, though it may perhaps at first appear to you, that
to treat of the principles of inquiry, in the physics of _matter_,
is to wander from the intellectual and moral speculations which
peculiarly concern us; it is in truth only as they are illustrative
of inquiries which we are to pursue in the _physiology of the mind_,
that I am led to make these general remarks. The principles of
philosophic investigation are, as I have already said, common to all
the sciences. By acquiring more precise notions of the objects of any
one of them, we can scarcely fail to acquire, in some degree, more
precision in our notions of every other, and each science may thus be
said to profit indirectly by every additional light that is thrown
upon each. It is by this diffusive tendency of its spirit, almost as
much as by its own sublime truths, and the important applications
of these to general physics, that the study of geometry has been of
such inestimable advantage to science. Those _precise definitions_
which insure to every word the same exact signification, in the mind
of every one who hears it pronounced, and that lucid progress in
the developement of truth after truth, which gives, even to ordinary
powers, almost the same facility of comprehension with the highest
genius, are unquestionably of the utmost benefit to the mathematical
student, while he is prosecuting his particular study, without any
contemplation of other advantages to be reaped from them. But there can
be no doubt that they are, at the same time, preparing his mind for
excellence in other inquiries, of which he has then no conception; that
he will ever after be less ready to employ, and be more quicksighted
than he would otherwise have been in detecting vague and indefinite
phraseology, and loose and incoherent reasoning; and that a general
spirit of exactness and perspicuity may thus at length be diffused in
society, which will extend its influence, not to the sciences merely,
but, in some faint degree, also to works of elegant literature, and
even to the still lighter graces of conversation itself. “The spirit of
geometrical inquiry,” says Fontenelle, “is not so exclusively attached
to geometry, as to be incapable of being applied to other branches of
knowledge. A work of morals, of politics, of criticism, or even of
eloquence, will, if all other circumstances have been the same, be the
more beautiful, for having come from the hand of a geometrician. The
order, the clearness, the precision, which, for a considerable time,
have distinguished works of excellence on every subject, have most
probably had their origin in that mathematical turn of thought, which
is now more prevalent than ever, and which gradually communicates
itself even to those who are ignorant of mathematics. It often happens
that a single great man gives the tone to the whole age in which he
lives; and we must not forget, that the individual who has the most
legitimate claim to the glory of having introduced and established a
new art of reasoning, was an excellent geometer.”[22] The philosopher
to whom this improvement of the art of reasoning is ascribed, is
evidently Descartes, whose claim is certainly much less legitimate than
that of our own illustrious countryman; but the works of Bacon were
not very extensively studied on the continent, at the time at which
Fontenelle wrote; while especially in France, the splendid reputation
of the great geometer, who shook, as much with his own wild hypothesis,
as with the weight of his reasoning, the almost idolatrous worship of
the God of the Schools, seemed to sweep before it the glory of every
other reformer. The instance of Descartes, however, is a still more
happy one than his ingenious countryman, who was himself a Cartesian,
could have imagined it to be. It is, indeed, impossible to conceive
a more striking example of that diffusive influence of the _general
spirit of scientific inquiry_, which I wish to illustrate; since, in
this instance, it survived the very system by which it was diffused;
all that was sceptical in that mixed system of scepticism and dogmatism
which constituted the philosophy of Descartes, having long continued,
and even now continuing, to operate beneficially, when scarcely a
doctrine of his particular philosophy retains its hold.
You will not then, I trust, take for granted, that precise notions as
to the objects of inquiry, in any science, even in the department of
external physics, can be so absolutely without benefit to our plans of
inquiry into mind, which must be pursued on the same principles, if it
be pursued with any prospect of success; and I may, therefore, safely
solicit your attention to a little farther elucidation of the two
objects which we have in view, in general physical inquiry, whether it
be relative to _matter_ or to _mind_.
To inquire into the composition of a substance, is to consider as
_one_, many substances, which have not the less an independent
existence, because they are in immediate proximity to each other. What
we term a _body_, however minute, is a multitude of bodies, or to
speak more exactly, an infinite number of bodies, which appear limited
to us, indeed, but may perhaps appear, in their true character of
infinity, to beings of a higher order, who may be able to distinguish
as _infinite_, what our limited senses allow us to perceive only as
_finite_. They are _one_, not in nature, but in our thought; as one
thousand individuals, that in nature must always be one thousand,
receive a sort of unity that is relative merely to our conception,
when ranked by us as a single regiment, or as many regiments become
_one_ by forming together an army. In the energies of external matter,
the innumerable separate bodies are thus regarded by us as _one_,
when the space which divides them is not measurable by our imperfect
vision, and as distinct or separate, when the space can be measured by
us. The _unity_ of the aggregate is here no absolute quality of the
mass, but is truly relative to the observer's power of distinguishing
the component parts; the mass being one or many, as his senses are
less or better able to distinguish these. This whole globe of earth,
with its oceans, and rivers, and mountains, and woods, and with all
the separate multitudes of its animated inhabitants, may seem to some
being of another species, only one continuous and uniform mass; as the
masses, that seem to us uniform and continuous, may seem a whole world
of separate and varied parts, to the insect population that swarms
upon its surface. “A single leaf of a tree,” to borrow an obvious
illustration from a French writer, “is a little world inhabited by
invisible animals, to whose senses it appears of immense extent, who
see in it mountains and abysses that are almost immeasurable, and who,
from one side of the leaf to the other, hold as little communication
with the opposite animalcula, who have their dwellings there, as we do
with our Antipodes.”[23]
Nothing can appear to our eyes more uniform than a piece of glass;
yet we know, from its composition, as a product of art, that it is
a congeries of bodies, which have no similarity to each other, and
which truly exist separately from each other, in the compound, as
they existed separately before the composition, though the lines of
space which divide them have now ceased to be visible to our weak
organs; and though, instead of being composed of alkaline and siliceous
matter, which we know to be different in their qualities, the beautiful
transparent substance, considered by us, were, as far as we know,
_simple_, in the chemical sense of the term, it would still be as
truly an aggregate of many bodies, not dissimilar, indeed, as in the
former case, but each similar in qualities to the aggregate itself.
The aggregate, in short, is, in every case, but a name invented by
ourselves; and what we term the constituent elements, are all that
truly exists. To inquire into the composition of a body, is, therefore,
only to inquire what these separate bodies are which we have chosen to
consider as _one_, or rather which are ranked by us as one, from their
apparent continuity.
I have dwelt the longer on this point of the _unity_ of an aggregate
mass, as derived from the mind of the observer only, and not from its
constituent bodies, which are truly separate and independent of each
other, and must always be separate and independent, whatever changes
they may seem to undergo, in the various processes of composition
and decomposition, because this is one of the most simple, and, at
the same time, one of the most convincing examples of a tendency of
the mind, which we shall often have occasion to remark in the course
of our intellectual analysis,--the tendency to ascribe to substances
without, as if existing in them like permanent physical qualities,
the relations which ourselves have formed, by the mere comparison of
objects with objects, and which, in themselves, as relations, are
nothing more than modifications of our own mind. It is very difficult
for us to believe, that, when we speak of a rock, or a mountain, or,
perhaps, still more, when we speak of a single leaf or blade of grass
as _one_, we speak of a plurality of independent substances, which
may exist apart, as they now exist together, and which have no other
unity than in our conception. It is the same with every other species
of relation. The tallness of a tree, the lowness of a shrub or weed,
as these relative terms are used by _us_ in opposition, do not express
any real quality of the tree, or shrub, or weed, but only the fact
that our mind has considered them together; all which they express, is
the mere comparison that is in _us_, not any quality in the external
objects; and yet we can scarcely bring ourselves to think, but that
independently of this comparison, there is some quality, in the tree,
which corresponds with our notion of tallness, and some opposite
quality in the shrub or weed, which corresponds with our notion of
shortness or lowness; so that the tree would deserve the name of tall,
though it were the only object in existence, and the shrub or weed, in
like manner, the epithet of lowly, though it alone existed, without
a single object with which it could be compared. These instances, as
I have said, are simple, but they will not be the less useful, in
preparing your minds for considering the more important natures of
relation in general, that imply, indeed, always some actual qualities
in the objects themselves, the perception of which leads us afterwards
to consider them as related, but no actual quality in either of the
objects that primarily and directly corresponds with the notion of the
relation itself, as there are qualities of objects that correspond
directly with our sensations of warmth or colour, or any other of the
sensations excited immediately by external things. The relation is, in
every sense of the word _mental_, not merely as being a feeling of
the mind, for our knowledge of the qualities of external things is,
in this sense, equally mental; but, as having its cause and origin
directly in the very nature of the _mind itself_, which cannot regard a
number of objects, without forming some comparison, and investing them
consequently with a number of relations. I have already spoken of the
intellectual medium, through which external objects become known to us;
and the metaphor is a just one. The medium, in this case, as truly as
in the transmission of light, communicates something of its own to that
which it conveys; and it is as impossible for us to perceive objects
long or often together, without that comparison which instantly invests
them with certain relations, as it would be for us to perceive objects,
for a single moment, free from the tint of the coloured glass through
which we view them. “Omnes perceptiones,” says Lord Bacon, using a
similar figure, “omnes perceptiones, tam sensus quam mentis, sunt ex
analogia hominis, non ex analogia universi; estque intellectus humanus
instar speculi inæqualis ad radios rerum, qui suam naturam naturæ rerum
immiscet, eamque distorquet et inficit.”
But, whatever may be thought of relations in general, there can be no
question, at least, as to the nature of that unity which we ascribe to
bodies. We have seen, that the substance, which, in thought we regard
as _one_, is, in truth, not _one_, but _many_ substances, to which
our thought alone gives unity; and that all inquiry, therefore, with
respect to the nature of a substance, as it exists in space, is an
inquiry into the nature of those separate bodies, that occupy the space
which we assign to the imaginary aggregate.
To dissipate this imaginary aggregate of our own creation, and to show
us those separate bodies which occupy its space, and are all that
nature created, is the great office of the analytic art of _Chemistry_,
which does for us only what the microscope does, that enables us to
see the small objects which are before us at all times, without our
being able to distinguish them. When a chemist tells us, that glass,
which appears to us one uniform substance, is composed of different
substances, he tells us, what, with livelier perceptive organs, we
might have known, without a single experiment; since the siliceous
matter and the alkali were present to us in every piece of glass, as
much before he told us of their presence, as after it. The art of
analysis, therefore, has its origin in the mere imperfection of our
senses, and is truly the art of the blind, whose wants it is always
striving to remedy, and always discovering sufficient proof of its
inability to remedy them.
We boast, indeed, of the chemical discoveries which we have made of
late, with a rapidity of progress as brilliant, as it is unexampled
in the history of any other science; and we boast justly, because we
have found, what the generations of inquirers that have preceded us
on our globe,--far from detecting,--had not even ventured to guess.
Without alluding to the agency of the _Galvanic power_,--by which all
nature seems to be assuming before us a different aspect--we have seen
fixed in the products of our common fires, and in the drossy rust of
metals, the purest part of that ethereal fluid which we breathe, and
the air itself, which was so long considered as simple, ceasing to
be an element. Yet whatever unsuspected similarities and diversities
of composition we may have been able to trace in bodies, all our
discoveries have not created a single new particle of matter. They
have only shown these to exist, where they always existed, as much
before our analysis as after it,--unmarked indeed, but unmarked,
only because our senses alone were not capable of making the nice
discrimination. If man had been able to perceive, with his mere organs
of sense, the different particles that form together the atmospheric
air--if he had at all times seen the portion of these which unites
with the fuel that warms him, enter into this union, as distinctly as
he sees the mass of fuel itself, which he flings into his furnace, he
could not have thought it a very great intellectual achievement, to
state in words so common and familiar a fact,--the mere well-known
change of place of a few well-known particles; and yet this is what,
in the imperfect state of his perceptive organs, he so proudly terms
his _Theory of Combustion_, the developement of which was hailed by a
wondering world, and in these circumstances justly hailed by it, as a
_scientific era_. To beings, capable of perceiving and distinguishing
the different particles, that form by their aggregation, those small
masses, which, after the minutest mechanical division of which we are
capable, appear atoms to us, the pride which we feel, in our chemical
analyses, must seem as ludicrous, as to us would seem the pride of the
blind, if one, who had never enjoyed the opportunity of beholding the
sun, were to boast of having discovered, by a nice comparison of the
changing temperature of bodies, that, during certain hours of the day,
there passed over our earth some great source of heat. The addition
of one new sense to us, who have already the inestimable advantages
which vision affords, might probably, in a few hours, communicate more
instruction, with respect to matter, than all which is ever to repay
and consummate the physical labours of mankind,--giving, perhaps, to a
single glance, those slow revelations of nature, which, one by one, at
intervals of many centuries, are to immortalize the future sages of our
race.
“All philosophy,” says an acute foreign writer, “is founded on these
two things,--that we have a great deal of curiosity, and very bad eyes.
In astronomy, for example, if our eyes were better, we should then see
distinctly, whether the stars really are, or are not, so many suns,
illuminating worlds of their own; and if, on the other hand, we had
less curiosity, we should then care a very little about this knowledge,
which would come pretty nearly to the same thing. But we wish to know
more than we see, and there lies the difficulty. Even if we saw _well_
the little which we do see, this would at least be some small knowledge
gained. But we observe it different from what it is; and thus it
happens, that a true philosopher passes his life, in not believing what
he sees, and in labouring to guess what is altogether beyond his sight.
I cannot help figuring to myself,” continues the same lively writer,
“that nature is a great public spectacle, which resembles that of the
opera. From the place at which we sit in the theatre, we do not see the
stage quite as it is. The scenes and machinery are arranged, so as to
produce a pleasing effect at a distance; and the weights and pullies,
on which the different movements depend, are hid from us. We therefore
do not trouble our heads with guessing, how this mechanical part of
the performance is carried on. It is perhaps only some mechanician,
concealed amid the crowd of the pit, who racks his brain about a
flight through the air, which appears to him extraordinary, and who
is seriously bent on discovering by what means it has been executed.
This mechanic, gazing, and wondering, and tormenting himself, in the
pit of the opera, is in a situation very like that of the philosopher
in the theatre of the world. But what augments the difficulty to the
philosopher, is, that, in the machinery which nature presents, the
cords are completely concealed from him,--so completely indeed, that
the constant puzzle has been to guess, what that secret contrivance is,
which produces the visible motions in the frame of the universe. Let us
imagine all the sages collected at an opera,--the Pythagorases, Platos,
Aristotles, and all those great names, which now-a-days make so much
noise in our ears. Let us suppose, that they see the flight of Phaeton,
as he is represented carried off by the winds; that they cannot
perceive the cords to which he is attached; and that they are quite
ignorant of every thing behind the scenes. It is a _secret virtue_,
says one of them, that carries off Phaeton. Phaeton, says another, is
composed of certain _numbers_, which cause him to ascend. A third says,
Phaeton has a certain _affection_ for the top of the stage. He does
not feel at his ease, when he is not there. Phaeton, says a fourth, is
not formed to fly; but he likes better to _fly_, than to leave the top
of the stage empty,--and a hundred other absurdities of the kind, that
might have ruined the reputation of antiquity, if the reputation of
antiquity, for wisdom could have been ruined. At last, come Descartes,
and some other moderns, who say, Phaeton ascends, because he is drawn
by cords, and because a weight, more heavy than he, is descending as
a counterpoise. Accordingly, we now no longer believe, that a body
will stir, unless it be drawn or impelled by some other body, or that
it will ascend, or descend, unless by the operation of some spring or
counterpoise; and thus to see nature, such as it really is, is to see
the back of the stage at the opera.”[24]
In this exposition of the phenomena of the universe, and of those
strange “follies of the wise,” which have been gravely propounded in
the systems of philosophers concerning them, there is much truth, as
well as happy pleasantry. As far, at least, as relates to matter,
considered merely as existing in space,--the first of the two lights
in which it may be physically viewed,--there can be no question,
that philosophy is nothing more than an endeavour to repair, by art,
the badness of our eyes, that we may be able to see what is actually
before us at every moment. To be fairly behind the scenes of the great
spectacle of nature, however, is something more than this. It is not
merely to know, at any one moment, that there are many objects existing
on the stage, which are invisible where the spectators sit, but to
know them as pieces of machinery, and to observe them operating in all
the wonders of the drama. It is, in short, to have that _second_ view
of nature, as existing in time as well as space, to the consideration
of which I am to proceed in my next Lecture.
FOOTNOTES:
[21] Nov. Org. Aph. 1.
[22] Preface aux Eloges--Œuvres, tom. v. p. 8.
[23] Fontenelle, Pluralité des Mondes, Conversat. 3.
[24] Fontenelle, Pluralité des Mondes, Conversat. 1.
LECTURE VI.
THE SAME SUBJECT CONTINUED.
In my last Lecture, Gentlemen, I considered, at some length, the nature
of _Physical Inquiry in general_, and stated to you, in particular, the
_two lights_, in which objects may be physically viewed, as existing
simply in _space_, or as existing in _time_,--the inquiries, with
respect to the one, having regard to the composition of bodies; the
inquiries, with respect to the other, having regard to the changes,
of which they are either the subjects or occasions, and consequently
to their susceptibilities or their powers--their susceptibilities of
being affected by other substances, their powers of affecting other
substances. I use the word _susceptibility_, you will perceive, as,
in this case, synonymous with what Mr Locke, and some other writers,
have denominated _passive power_, to avoid the apparent verbal
contradiction, or at least the ambiguity, which may arise from annexing
the term _passive_ to a word, which is generally employed to signify,
not the _subject_ of change, but the cause or occasion of change.
Of these two points of view, then, in which an object may be
regarded, when the question is put, What is it? we have seen, I hope,
sufficiently distinctly, the nature of one. If, in answering the
question, we regard the object merely as it exists in space, and say,
that it is a _compound_ of certain substances, we mean nothing more,
than that, in the portion of space, which we conceive to be occupied
by this one imaginary aggregate, there is truly a plurality of bodies,
which, though seemingly contiguous, have an existence, as separate and
independent of each other, as if they were at the most remote distance;
the one aggregate being nothing more than a name for these separate
bodies, to which ourselves give all the unity which they have, merely
by considering them as _one_.