Mr Condorcet's conjecture concerning the organic perfectibility of man,
and the indefinite prolongation of human life--Fallacy of the argument,
which infers an unlimited progress from a partial improvement, the
limit of which cannot be ascertained, illustrated in the breeding of
animals, and the cultivation of plants.
The last question which Mr Condorcet proposes for examination is the
organic perfectibility of man. He observes that if the proofs which
have been already given and which, in their development will receive
greater force in the work itself, are sufficient to establish the
indefinite perfectibility of man upon the supposition of the same
natural faculties and the same organization which he has at present,
what will be the certainty, what the extent of our hope, if this
organization, these natural faculties themselves, are susceptible of
amelioration?
From the improvement of medicine, from the use of more wholesome food
and habitations, from a manner of living which will improve the
strength of the body by exercise without impairing it by excess, from
the destruction of the two great causes of the degradation of man,
misery, and too great riches, from the gradual removal of transmissible
and contagious disorders by the improvement of physical knowledge,
rendered more efficacious by the progress of reason and of social
order, he infers that though man will not absolutely become immortal,
yet that the duration between his birth and natural death will increase
without ceasing, will have no assignable term, and may properly be
expressed by the word 'indefinite'. He then defines this word to mean
either a constant approach to an unlimited extent, without ever
reaching it, or an increase. In the immensity of ages to an extent
greater than any assignable quantity.
But surely the application of this term in either of these senses to
the duration of human life is in the highest degree unphilosophical and
totally unwarranted by any appearances in the laws of nature.
Variations from different causes are essentially distinct from a
regular and unretrograde increase. The average duration of human life
will to a certain degree vary from healthy or unhealthy climates, from
wholesome or unwholesome food, from virtuous or vicious manners, and
other causes, but it may be fairly doubted whether there is really the
smallest perceptible advance in the natural duration of human life
since first we have had any authentic history of man. The prejudices of
all ages have indeed been directly contrary to this supposition, and
though I would not lay much stress upon these prejudices, they will in
some measure tend to prove that there has been no marked advance in an
opposite direction.
It may perhaps be said that the world is yet so young, so completely in
its infancy, that it ought not to be expected that any difference
should appear so soon.
If this be the case, there is at once an end of all human science. The
whole train of reasonings from effects to causes will be destroyed. We
may shut our eyes to the book of nature, as it will no longer be of any
use to read it. The wildest and most improbable conjectures may be
advanced with as much certainty as the most just and sublime theories,
founded on careful and reiterated experiments. We may return again to
the old mode of philosophising and make facts bend to systems, instead
of establishing systems upon facts. The grand and consistent theory of
Newton will be placed upon the same footing as the wild and eccentric
hypotheses of Descartes. In short, if the laws of nature are thus
fickle and inconstant, if it can be affirmed and be believed that they
will change, when for ages and ages they have appeared immutable, the
human mind will no longer have any incitements to inquiry, but must
remain fixed in inactive torpor, or amuse itself only in bewildering
dreams and extravagant fancies.
The constancy of the laws of nature and of effects and causes is the
foundation of all human knowledge, though far be it from me to say that
the same power which framed and executes the laws of nature may not
change them all 'in a moment, in the twinkling of an eye.' Such a
change may undoubtedly happen. All that I mean to say is that it is
impossible to infer it from reasoning. If without any previous
observable symptoms or indications of a change, we can infer that a
change will take place, we may as well make any assertion whatever and
think it as unreasonable to be contradicted in affirming that the moon
will come in contact with the earth tomorrow, as in saying that the sun
will rise at its usual time.
With regard to the duration of human life, there does not appear to
have existed from the earliest ages of the world to the present moment
the smallest permanent symptom or indication of increasing
prolongation. The observable effects of climate, habit, diet, and other
causes, on length of life have furnished the pretext for asserting its
indefinite extension; and the sandy foundation on which the argument
rests is that because the limit of human life is undefined; because you
cannot mark its precise term, and say so far exactly shall it go and no
further; that therefore its extent may increase for ever, and be
properly termed indefinite or unlimited. But the fallacy and absurdity
of this argument will sufficiently appear from a slight examination of
what Mr Condorcet calls the organic perfectibility, or degeneration, of
the race of plants and animals, which he says may be regarded as one of
the general laws of nature.
I am told that it is a maxim among the improvers of cattle that you may
breed to any degree of nicety you please, and they found this maxim
upon another, which is that some of the offspring will possess the
desirable qualities of the parents in a greater degree. In the famous
Leicestershire breed of sheep, the object is to procure them with small
heads and small legs. Proceeding upon these breeding maxims, it is
evident that we might go on till the heads and legs were evanescent
quantities, but this is so palpable an absurdity that we may be quite
sure that the premises are not just and that there really is a limit,
though we cannot see it or say exactly where it is. In this case, the
point of the greatest degree of improvement, or the smallest size of
the head and legs, may be said to be undefined, but this is very
different from unlimited, or from indefinite, in Mr Condorcet's
acceptation of the term. Though I may not be able in the present
instance to mark the limit at which further improvement will stop, I
can very easily mention a point at which it will not arrive. I should
not scruple to assert that were the breeding to continue for ever, the
head and legs of these sheep would never be so small as the head and
legs of a rat.
It cannot be true, therefore, that among animals, some of the offspring
will possess the desirable qualities of the parents in a greater
degree, or that animals are indefinitely perfectible.
The progress of a wild plant to a beautiful garden flower is perhaps
more marked and striking than anything that takes place among animals,
yet even here it would be the height of absurdity to assert that the
progress was unlimited or indefinite.
One of the most obvious features of the improvement is the increase of
size. The flower has grown gradually larger by cultivation. If the
progress were really unlimited it might be increased ad infinitum, but
this is so gross an absurdity that we may be quite sure that among
plants as well as among animals there is a limit to improvement, though
we do not exactly know where it is. It is probable that the gardeners
who contend for flower prizes have often applied stronger dressing
without success. At the same time it would be highly presumptuous in
any man to say that he had seen the finest carnation or anemone that
could ever be made to grow. He might however assert without the
smallest chance of being contradicted by a future fact, that no
carnation or anemone could ever by cultivation be increased to the size
of a large cabbage; and yet there are assignable quantities much
greater than a cabbage. No man can say that he has seen the largest ear
of wheat, or the largest oak that could ever grow; but he might easily,
and with perfect certainty, name a point of magnitude at which they
would not arrive. In all these cases therefore, a careful distinction
should be made, between an unlimited progress, and a progress where the
limit is merely undefined.
It will be said, perhaps, that the reason why plants and animals cannot
increase indefinitely in size is, that they would fall by their own
weight. I answer, how do we know this but from experience?--from
experience of the degree of strength with which these bodies are
formed. I know that a carnation, long before it reached the size of a
cabbage, would not be supported by its stalk, but I only know this from
my experience of the weakness and want of tenacity in the materials of
a carnation stalk. There are many substances in nature of the same size
that would support as large a head as a cabbage.
The reasons of the mortality of plants are at present perfectly unknown
to us. No man can say why such a plant is annual, another biennial, and
another endures for ages. The whole affair in all these cases, in
plants, animals, and in the human race, is an affair of experience, and
I only conclude that man is mortal because the invariable experience of
all ages has proved the mortality of those materials of which his
visible body is made:
What can we reason, but from what we know?
Sound philosophy will not authorize me to alter this opinion of the
mortality of man on earth, till it can be clearly proved that the human
race has made, and is making, a decided progress towards an illimitable
extent of life. And the chief reason why I adduced the two particular
instances from animals and plants was to expose and illustrate, if I
could, the fallacy of that argument which infers an unlimited progress,
merely because some partial improvement has taken place, and that the
limit of this improvement cannot be precisely ascertained.
The capacity of improvement in plants and animals, to a certain degree,
no person can possibly doubt. A clear and decided progress has already
been made, and yet, I think, it appears that it would be highly absurd
to say that this progress has no limits. In human life, though there
are great variations from different causes, it may be doubted whether,
since the world began, any organic improvement whatever in the human
frame can be clearly ascertained. The foundations, therefore, on which
the arguments for the organic perfectibility of man rest, are unusually
weak, and can only be considered as mere conjectures. It does not,
however, by any means seem impossible that by an attention to breed, a
certain degree of improvement, similar to that among animals, might
take place among men. Whether intellect could be communicated may be a
matter of doubt: but size, strength, beauty, complexion, and perhaps
even longevity are in a degree transmissible. The error does not seem
to lie in supposing a small degree of improvement possible, but in not
discriminating between a small improvement, the limit of which is
undefined, and an improvement really unlimited. As the human race,
however, could not be improved in this way, without condemning all the
bad specimens to celibacy, it is not probable that an attention to
breed should ever become general; indeed, I know of no well-directed
attempts of this kind, except in the ancient family of the
Bickerstaffs, who are said to have been very successful in whitening
the skins and increasing the height of their race by prudent marriages,
particularly by that very judicious cross with Maud, the milk-maid, by
which some capital defects in the constitutions of the family were
corrected.
It will not be necessary, I think, in order more completely to shew the
improbability of any approach in man towards immortality on earth, to
urge the very great additional weight that an increase in the duration
of life would give to the argument of population.
Many, I doubt not, will think that the attempting gravely to controvert
so absurd a paradox as the immortality of man on earth, or indeed, even
the perfectibility of man and society, is a waste of time and words,
and that such unfounded conjectures are best answered by neglect. I
profess, however, to be of a different opinion. When paradoxes of this
kind are advanced by ingenious and able men, neglect has no tendency to
convince them of their mistakes. Priding themselves on what they
conceive to be a mark of the reach and size of their own
understandings, of the extent and comprehensiveness of their views,
they will look upon this neglect merely as an indication of poverty,
and narrowness, in the mental exertions of their contemporaries, and
only think that the world is not yet prepared to receive their sublime
truths.
On the contrary, a candid investigation of these subjects, accompanied
with a perfect readiness to adopt any theory warranted by sound
philosophy, may have a tendency to convince them that in forming
improbable and unfounded hypotheses, so far from enlarging the bounds
of human science, they are contracting it, so far from promoting the
improvement of the human mind, they are obstructing it; they are
throwing us back again almost into the infancy of knowledge and
weakening the foundations of that mode of philosophising, under the
auspices of which science has of late made such rapid advances. The
present rage for wide and unrestrained speculation seems to be a kind
of mental intoxication, arising, perhaps, from the great and unexpected
discoveries which have been made of late years, in various branches of
science. To men elate and giddy with such successes, every thing
appeared to be within the grasp of human powers; and, under this
illusion, they confounded subjects where no real progress could be
proved with those where the progress had been marked, certain, and
acknowledged. Could they be persuaded to sober themselves with a little
severe and chastised thinking, they would see, that the cause of truth,
and of sound philosophy, cannot but suffer by substituting wild flights
and unsupported assertions for patient investigation, and well
authenticated proofs.
Mr Condorcet's book may be considered not only as a sketch of the
opinions of a celebrated individual, but of many of the literary men in
France at the beginning of the Revolution. As such, though merely a
sketch, it seems worthy of attention.