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strata. He has three toes in the more recent strata, and
four toes in the ear Her ; and, curiously enough, the
complete series is found in America, where there were
no horses at the time of its discovery by Europeans.
Now Man, on the other hand, is a complex-brained
animal, differing in this way and in some others from all
other mammals ; but since in other respects his whole
structure shows relationship with them, and especially
with the apes, it is probable that he is descended from
an ancestor with a simpler brain and a structure
generally bearing more resemblance to the common
Simian type. The problem is to find this ancestor.



296 VIRCHOW ON THE TEACHING OF SCIENCE.

There is no trace of him in the quaternary strata,
because the quaternary men are still men so far as their
bony structure is concerned, and we have no evidence
about the complexity of their brains, the pointedness of
their ears, or the hairy covering of their bodies. Nor,
as yet, has any decisive discovery been made of the
remains of man, or of any sufficiently man-like animal to
count as his ancestor, in the tertiary strata. Until we
find the missing link, says Virchow, the descent of man
from an ape-like ancestor is not a conquest of science.
When we do find the missing link, it will be a conquest
of science.

It will naturally, I think, strike anyone who, though
a layman, has gained a certain amount of secondhand
knowledge of this subject from books, that in this view
of the two cases the evidence of fossils is made rather
too much of, while other kinds of evidence are wholly
ignored. It is a bold thing to criticise the judgment of
a pathologist upon general doctrines of biology, when
one is oneself not a biologist in any respect. I will
therefore shelter myself under authority.

4 When we confine our attention to any one form
(says Darwin) we are deprived of the weighty arguments
derived from the nature of the affinities which connect
together whole groups of organisms their geographical
distribution in past and present times, and their geolo-
gical succession. The homological structure, embryolo-
gical development, and rudimentary organs of a species,
whether it be man or any other animal, to which our
attention may be directed, remain to be considered ; but
these great classes of facts afford, as it appears to me,



VIRCHOW ON THE TEACHING OF SCIENCE. 297

ample and conclusive evidence in favour of the principle
of gradual evolution.' l

For example, it happens that the missing link
between man and the anthropoids has not yet been
found ; but there is a Miocene link which bridges a
greater gulf between two other families of apes. 2 So
that kinds of evidence may exist in regard to an order
of animals which are wanting in the case of an indivi-
dual family of the order. But both the general analogy
of Nature, and the three great classes of facts considered
by Darwin in the special case of Man, are apparently
reckoned by Yirchow as of no practical weight, until the
bones of the missing link are safe in the glass cases of
a geological museum. I say apparently, because it
would be insulting a great man to suppose that he really
held such an opinion, which, moreover, is inconsistent
with the preface to the English translation of his speech.
In fact, this admirable speech, in so many ways like that
of a cabinet minister reassuring his Opposition, contains
more than one passage which, especially when isolated
and printed in capitals, it is easy for the Opposition to
interpret in a sense more favourable to its own views
than that which the speaker had in his mind.

Not only, however, are important kinds of evidence
left out of count, but as it seems to me under guidance,
as before the cogency of the evidence from fossils is
somewhat overrated. We must be very careful not to
be too sure of these conclusions, lest we should teach as
established results of science what are, after all, remote
and precarious inferences.

1 Preface to Descent of Man. * Descent of Man, i. 197.



298 VIRCHOW ON THE TEACHING OF SCIENCE.

6 We must recollect (says Huxley) that any human
belief, however broad its basis, however defensible it
may seem, is, after all, only a probable belief, and that
our widest and safest generalizations are simply state-
ments of the highest degree of probability. Though we
are quite clear about the constancy of the order of Nature,
at the present time, and in the present state of things,
it by no means necessarily follows that we are justified
in expanding this generalization into the infinite past,
and in denying, absolutely, that there may have been a
time when Nature did not follow a fixed order, when
the relations of cause and effect were not definite, and
when extra-natural agencies interfered with the general
course of Nature.' 1

The fact is, we are not absolutely and theoretically
certain that these old three-toed and four-toed horse-
bones were not made, on purpose to deceive us, by the
devil ; himself, according to Cuvier, a horned and hoofed,
and therefore graminivorous animal, with more than one
toe on the hinder limb. 2

This kind of tangible evidence, which gives us some-
thing definite to lay hold of, is peculiarly apt to produce
conviction without being properly understood. ' Is it
really true that our horses are descended from an ances-
tor with three toes, who lived a long time ago ? ' ' Why,
of course it is ; here's his hock.' It is something like
what occurs in the stage-plays, when somebody rushes
in to the hero, and says : ' Take these papers and guard

1 American Addresses, p. 3.

2 The devil is said to have appeared to Cuvier and threatened to eat
him. f Horns ? Hoofs ? ' said Cuvier. ' Graminivorous. Can't eat me.'
' All flesh is grass/ replied the devil, with that fatal habit of misapplying
Scripture which has always clung to him.



VIRCHOW ON THE TEACHING OF SCIENCE. 299

them carefully ; they prove that you are a prince.'
The sight of the bundle neatly done up in red tape pro-
duces conviction in a moment. But we subsequently
reflect that it may be a somewhat delicate and difficult
matter to prove by the aid of papers that a man is him-
self or anybody else ; and that there are other methods
of establishing personal identity, which are not less valid
in the courts.

I am not disparaging this palasontological evidence
for the descent of the horse, or saying a word inconsistent
with Huxley's conclusion that it is demonstration, in the
only sense in which demonstration can apply to an his-
torical fact. What I wish to point out is that it con-
tains many steps of reasoning which are rather difficult
to the apprehension of anyone who is not a specialist,
and which involve considerations somewhat abstract and
remote from the tangible facts on which they are founded.
The succession of strata in time, and the mode of their
deposition, especially the relations of European strata
with American ; these, and some other doctrines of
geology, are involved in the argument. Now, however
certain they may be, the evidence upon which they are
established is circumstantial and remote. It is easy
enough to the geologist, who is accustomed to it, but it
does require special study to master it fully. And there
is no trace whatever of these difficulties in the statement
' Here's his hock.' Convincing as that statement is, it
does not carry along with the conviction a fair estimate
of the evidence on which it is based.

With this consideration in mind, let us compare
again the evidence for the descent of man with that for
the descent of the horse. The generation of men of



300 VIRCHOW ON THE TEACHING OF SCIENCE.

any given race now existing is descended from parents
who on the average differed imperceptibly from them-
selves. This has not gone on for ever, because physical
evidence proves a beginning to the present state of the
earth. Were the first men also the offspring of parents
who differed imperceptibly from themselves, yet so that
the imperceptible difference came just where we draw
the line between man and not-man ? * Such a line would
of course be arbitrary, but we may suppose a certain
hundred generations, the change in each being imper-
ceptible, but still such that we should call the first not-
men and the last men. This is the supposition of a
non-human ancestor, as made by the evolutionist. v If
this supposition is rejected, the first men may have ori-
ginated (1) from parents differing largely from them in
structure ; (2) from non-living matter, or (3) from non-
existence, being men from the moment they began to
be. We are not bound to make any supposition at all
about the origin of the first men ; but if we do make
any supposition, it must be one of these.

Suppose, however, that we want not merely to make
a supposition, but to infer from the facts before us what
actually happened. Then we must make the assumption
that there is some sort of uniformity in nature.<*flWithout
this we cannot infer at all, for inference consists in
transferring the experience which we have had under
certain conditions to events happening under like con-
ditions, of which we have not had experience. It is
true that we cannot be absolutely sure of the uniformity
of nature, or that our present conception of it is right :
but still it is the only thing we have to go upon.
Human knowledge is never absolutely and theoretically



.



VIRCHOW ON THE TEACHING OF SCIENCE. 301

certain, but a great deal of it is practically certain,
which is all we want.

Now the production of man from non-li ving matter,
or the coming of any kind of matter into existence out
of nothing, are things so entirely without parallel in our
existing experience that we cannot infer them unless
our experience entirely changes its character. If clay
or mould would form itself into a human body a few
times, we might learn something about the conditions
under which such a transformation takes place, which
would enable us to infer that it had taken place before.
If matter would occasionally come into existence out of
nothing, we might say what kind of matter was most
likely to do such a thing ; whether buttons or sovereigns
were most gifted with this faculty, and so on. But even
so, some time must elapse before we could infer, because
our whole conception of the order of things would be
turned topsy-turvy X

If, therefore, we are to infer anything at all about ,
the origin of the first men, we must infer that they
descended from non-human ancestors. What sort of
ancestors these were, is, in the present state of know-
ledge, matter of conjecture merely. To guide this con-
jecture, we have ' the homological structure, embryo-
logical development, and rudimentary organs ' of exist-
ing men. Tha evidence of this kind set forth by Darwin
seems to point with very great probabili ty to an ancestor
more ape-like than man. Still these indications are not
so clear and unmistakable that a less ape-like ancestor,
as Yogt supposes, would be inconsistent with the unifor-
mity of nature. We are dealing with a long series of
similar events, the descent of each successive generation



802 VIRCHOW ON THE TEACHING OF SCIENCE.

from one very like it ; and though each event is an ex-
ample of what occurs habitually in our experience, yet
the effect of the whole series of such events is something
of which we can only get knowledge by means of palseon-
tological evidence. We can only, therefore, infer with
a very moderate amount of probability that men are
descended from this sort of animal or that sort of animal.
This is the point which will be set at rest by the missing
link. But I venture to think that the evidence for the
descent of man from some non-human ancestor will be
but very slightly strengthened by that discovery ; and
that it is now not perceptibly less cogent than that for
the descent of the horse.

For observe that each alike depends on the assump-
tion of the uniformity of Nature, That being given,
the descent of man follows from the originally fluid
condition of the earth, proved by physical observation
and reasoning. Failing that, the evidence for the descent
of the horse vanishes into thin air* It is not the least
bit more likely that man arose out of the dust of the
earth than that the devil made the American horse-
bones. Worse than this, quaternary man goes too.
' Quaternary man,' says Virchow, ' is no longer a problem,
but a real doctrine.' But how do you know that the
devil did not make the fossil men and all the flint imple-
ments ? This also is quite as likely as that a human
body was ever formed by the direct transformation of
non-living matter*

' Well then,' I hear my anxious friend say, with a
sigh of relief, ' we need not believe even in the antiquity
of man, or the evolution of horses. They are all doubt-
ful together.' My good soul, no student of science wants



VIRCHOW ON THE TEACHING OF SCIENCE. 303

you to believe anything unless you understand the
nature of the evidence for it, and then only to the
extent which is warranted by the evidence. There is
no occasion for you to form an opinion about these
questions. You need have no fear of being singular.
There is always the defence of the ensign who was
asked if he had seen Punch : ' Well, you know, the fact
is, I am not a reading man.' But if you wish to form
an opinion, there are many excellent manuals in which
you may learn the nature of the evidence and the methods
of reasoning on which such an opinion should be based.
If your opinion should be adverse to the views held by
other scientific students, you will do great service by
stating your objections. Do not suppose for a moment
that we want you to believe on any other terms.

But what we do hope, for your sake, is this : that
you will not allow any dishonest person to persuade you
to ^believe strongly in the doctrine of evolution, because
Virchow has admitted that certain parts of it are not
yet absolutely proved. It is one thing to believe that a
doctrine is false, and quite another thing to admit a
theoretical doubt about it.

I say a theoretical doubt, because it is a doubt founded
on the necessary imperfection of all human knowledge,
and not on any practical defect of the evidence. For a
doubt precisely similar in kind, though rather greater in
degree, attaches to the statement that the Eussians took
Plevna last year. The evidence for the truth of this
statement is, I admit, very strong, and I suppose no sane
man would be disposed to question it for a moment.
We have the testimony of all the newspaper corre-
spondents, the course of subsequent events, the special



304 VIRCHOW ON THE TEACHING OF SCIENCE.

information of the Government, and literally a whole
army of witnesses besides. Still, the Eussians may have
been one and all under a continuous hallucination, and
be even now in imminent danger from Osman Pasha.
Or those rascally papers may have laid their heads
together to deceive the whole British nation, down to
this hour. Either of these suppositions is a great deal
more likely than that the devil made the old horse-bones,
or that clay was transformed into a human body. To
be sure, they contradict our experience of the uniform-
ities of human action to such an extent that we cannot
seriously entertain them. But the uniformities of
human action are known with far less accuracy and
completeness than the uniformities which characterize
the generation of living bodies^. One man under an
hallucination is common enough ; one newspaper wrong
in its facts is well within our experience. So that we
have something to go upon in conceiving a widespread
delusion. But a man without any mother at all, a real
son of the soil, is a thing our experience gives us no
help towards conceiving.

If you went to a man of the world with this doubt
about Plevna, urging upon him that newspapers were
often mistaken, and begging him to consider it in buying
stocks, he would either take you for a lunatic and
humour your fancy, or he would say : ' Don't be so
silly ; I have no patience with you.' But the student
of science is obliged to have a great deal of patience,
and desires to have more.

It seems, then, that the difference between the
doctrines of the descent of horses and of the descent of
men is not that one is a known fact and the other a con-



VIRCHOW ON THE TEACHING OF SCIENCE. 305

jecture, because each of them is practically as certain
as such a doctrine can be, though subject to the theo-
retical doubt which attaches to all human knowledge.
And yet there certainly is a great difference between
the highly abstract and general considerations which go
to establish the one, and the more concrete, but still
rather difficult, arguments which prove the other. The
evidence in the two cases appeals to two different classes
of minds. The inference from a modern horse-bone to
the horse whose bone it was is a tolerably easy one,
which can be brought home to many minds. From a
fossil bone to the ancient animal is a more remote infer-
ence, which was at first made with considerable diffi-
culty ; yet still any person of ordinary intelligence may
be expected to grasp it. Then the geological inferences,
from stratified rocks to the sea or river which deposited
them, from successive position to successive age, and so
on, may have their way smoothed by concrete examples
so as to carry their due weight without much mental
strain. The biological inferences which connect the
modern horse with his fossil representative, based on
the structure of corresponding parts and the develop-
ment of the colt, involve reasoning of a rather more
abstract kind. But the whole of this evidence may be
fairly presented to a mind which is still incompetent to
form that general conception of the uniformity of nature
which makes the directly inorganic origin of man a
supposition not to be seriously entertained for a moment.
To grasp the idea of any law of nature requires a con-
siderable effort of abstraction, and that the idea may be
of any real use it must be founded on acquaintance with
the facts that come under the law. The general con-
VOL. n. x



306 VIRCHOW ON THE TEACHING OF SCIENCE.

ception of law which is contravened by the supposition
in question has to be abstracted from a knowledge of
many different laws, dynamical, physical, chemical, bio-
logical. This conception, therefore, implies a very wide
and many-sided training in facts, a very deep and
thorough training in logic, as its foundation. Much
education is required to enable the learner really to
estimate the evidence for the many-toed horse ; much
more is wanted for the clear comprehension of the
evidence for the simpler-brained man.

Here the education question, which has been under-
lying our whole discussion, is brought to the front. It
is clear that the evidence for these doctrines cannot be
taught until a late period in education. What are we
to do in the earlier periods ? Shall we say : ' Horses
had three-toed and four-toed ancestors ; by-and-by you
will learn how this was found out. We think, but are
not quite sure, that men had simpler-brained ancestors ;
by-and-by you will learn why we think so ' ?

It seems to me that this is the very worst thing we
can do ; that if we say this, we shall not only confuse
the child's head at the time with abstractions which it
is impossible that he should really grasp, but we shall
effectually prevent him from learning them properly in
the future. The true rule, I believe, is this : Before
teaching any doctrine p , wait until the nature of the evidence
for it can be understood.

This appears at first sight a very hard thing to do.
Yet it is really involved in Pestalozzi's great principle
that children should be made to find out things for
themselves. To make clearer the reasons for it, I will
consider a case which has the advantage of not being at



VIRCHOW ON THE TEACHING OF SCIENCE. 307

the present moment in controversy ; the case of the
teaching of chemistry. Suppose we were to begin
teaching chemistry by saying that carbon is made up of
atoms which have four hooks or hands by which they
can hold on to other atoms ; that oxygen atoms have
two hooks, and hydrogen atoms one. Consequently we
can hook two hydrogen atoms to an oxygen atom, and
this makes water ; or we can hook two oxygen atoms
to a carbon atom, making carbonic aoid ; or we can
hook four hydrogen atoms to a carbon atom, making
marsh-gas. Then we should utterly confuse the learner's
mind, and prevent him from learning chemistry after-
wards. These statements belong to the doctrine of
atomicities. Nobody doubts that these statements re-
present, in highly metaphorical language, real facts of
chemical action ; only Sir Benjamin Brodie says that since
the hydrogen atoms occur always in even numbers in
compounds made of carbon, oxygen, and hydrogen, we
ought to fasten them together in pairs, and call each
pair an atom with two hooks. What sort of thing we
should find, if we knew all about these atoms, answering
to the metaphor of the hooks, nobody knows. Without
a knowledge of the facts which they symbolize, these
statements are mere useless nonsense in anybody's
mind. They are worse than useless ; for they make
him think he knows the facts, and so prevent him from
really getting to know them.

On the other hand, we may follow Dr. Williamson's
method, show the children how to make carbonic acid,
and then pour it on a candle to put it out ; burn hydro-
gen to produce water, and so forth. When a few of
the commoner substances are real things to them, whose

x 2



308 VIRCHOW ON THE TEACHING OF SCIENCE.

properties they are familiar with, they may learn to
weigh and measure. Then the law of definite propor-
tions becomes legitimate teaching, and the law of gaseous
volumes. It is only necessary to verify these in a few
cases, that the nature of the evidence for them may be
understood.

Here arises a typical question. How, at this point,
shall we deal with the doctrine of molecules ? The
chemical evidence for it may now be clearly under-
stood ; but the chemical evidence leaves it still a hypo-
thesis. It becomes quite clear that the hypothesis
explains the facts, and links them together : but it does
not become clear that no other hypothesis will explain
the facts. I think there is every reason why it should
be taught as a hypothesis ; there are materials in the
pupil's mind for estimating the value of the hypothesis
in making the facts clear to him, and also for under-
standing why, at present, it is only hypothesis. And I
further think that, at this stage, no great harm will be
done by telling him that when he has learned enough
about heat and motion, he will find the hypothesis
turned into a demonstrated fact. i^

The doctrine of atomicities depends upon the various
combinations of the same set of elements with one
another. The facts on which it is based may be
described without introducing any totally new concep-
tions ; the nature of the evidence for it may therefore"
be understood by a pupil at this stage, without any
further experiment. I am not, of course, speaking of
the training of a specialist, but of that which should
form a part of general culture.

Of these two methods of teaching, there can be no



VIRCHOW ON THE TEACHING OF SCIENCE. 309

doubt that the latter will commend itself to the common
sense of every reasonable man. It insures that the
pupil shall learn to do things, that is, either to deal
practically with certain objects, or to use in thinking
certain conceptions ; not to think he knows things of
which he is really ignorant. And all the time it
cultivates a habit of accepting beliefs on the strength of
the evidence for them, of preferring true and honest
knowledge to sham knowledge. And it secures us
against the teaching, as known fact, of that which is not
known fact. The only danger in this respect is in the
doctrine of molecules ; and here we must impress very
carefully on our teachers that they should not miss the
important lesson in logic and in scientific procedure
involved in the conception of a hypothesis, and in
recognizing the imperfection of the evidence which
fails to exclude all other hypotheses.

Now let us go back from this chemical doctrine of
atomicities to the doctrine of evolution. In what form
shall we have the doctrine of evolution taught to our
children ? Certainly not as a dogma to be accepted on
the authority of the teacher, evidence for which may be
forthcoming afterwards. Certainly not at all until our
children are competent to understand the nature of the


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