Thoughts on Man

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Dr. Price has calculated the produce of one penny, put out at
the commencement of the Christian era to five per cent. compound
interest, and finds that in the year 1791 it would have increased
to a greater sum than would be contained in three hundred
millions of earths, all solid gold. But what has this to do with
the world in which we live? Did ever any one put out his penny
to interest in this fashion for eighteen hundred years? And, if
he did, where was the gold to be found, to satisfy his demand?

Morse, in his American Gazetteer, proceeding on the principles of
Malthus, tells us that, if the city of New York goes on
increasing for a century in a certain ratio, it will by that time
contain 5,257,493 inhabitants. But does any one, for himself or
his posterity, expect to see this realised?

Blackstone, in his Commentaries on the Laws of England, has
observed that, as every man has two ancestors in the first
ascending degree, and four in the second, so in the twentieth
degree he has more than a million, and in the fortieth the square
of that number, or upwards of a million millions. This statement
therefore would have a greater tendency to prove that mankind in
remote ages were numerous, almost beyond the power of figures to
represent, than the opposite doctrine of Malthus, that they have
a perpetual tendency to such increase as would infallibly bring
down the most tremendous calamities on our posterity.

Berkeley, whom I have already referred to on another subject, and
who is admitted to be one of our profoundest philosophers, has
written a treatise[48] to prove, that the mathematicians, who
object to the mysteries supposed to exist in revealed religion,
"admit much greater mysteries, and even falshoods in science, of
which he alleges the doctrine of fluxions as an eminent
example[49]." He observes, that their conclusions are
established by virtue of a twofold error, and that these errors,
being in contrary directions, are supposed to compensate each
other, the expounders of the doctrine thus arriving at what they
call truth, without being able to shew how, or by what means they
have arrived at it.

[48] The Analyst.

[49] Life of Berkeley, prefixed to his Works.

It is a memorable and a curious speculation to reflect, upon how
slight grounds the doctrine of "thousands and thousands of suns,
multiplied without end, and ranged all around us, at immense
distances from each other, and attended by ten thousand times ten
thousand worlds," mentioned in the beginning of this Essay, is
built. It may be all true. But, true or false, it cannot be
without its use to us, carefully to survey the road upon which we
are advancing, the pier which human enterprise has dared to throw
out into the vast ocean of Cimmerian darkness. We have
constructed a pyramid, which throws into unspeakable contempt the
vestiges of ancient Egyptian industry: but it stands upon its
apex; it trembles with every breeze; and momentarily threatens to
overwhelm in its ruins the fearless undertakers that have set it
up.

It gives us a mighty and sublime idea of the nature of man, to
think with what composure and confidence a succession of persons
of the greatest genius have launched themselves in illimitable
space, with what invincible industry they have proceeded, wasting
the midnight oil, racking their faculties, and almost wearing
their organs to dust, in measuring the distance of Sirius and the
other fixed stars, the velocity of light, and "the myriads of
intelligent beings formed for endless progression in perfection
and felicity," that people the numberless worlds of which they
discourse. The illustrious names of Copernicus, Galileo,
Gassendi, Kepler, Halley and Newton impress us with awe; and, if
the astronomy they have opened before us is a romance, it is at
least a romance more seriously and perseveringly handled than any
other in the annals of literature.

A vulgar and a plain man would unavoidably ask the astronomers,
How came you so familiarly acquainted with the magnitude and
qualities of the heavenly bodies, a great portion of which, by
your own account, are millions of millions of miles removed from
us? But, I believe, it is not the fashion of the present day to
start so rude a question. I have just turned over an article on
Astronomy in the Encyclopaedia Londinensis, consisting of one
hundred and thirty-three very closely printed quarto pages, and
in no corner of this article is any evidence so much as hinted
at. Is it not enough? Newton and his compeers have said it.

The whole doctrine of astronomy rests upon trigonometry, a branch
of the science of mathematics which teaches us, having two sides
and one angle, or two angles and one side, of a triangle given
us, to construct the whole. To apply this principle therefore to
the heavenly bodies, it is necessary for us to take two stations,
the more remote from each other the better, from which our
observations should be made. For the sake of illustration we
will suppose them to be taken at the extremes of the earth's
diameter, in other words, nearly eight thousand miles apart from
each other, the thing itself having never been realised to that
extent. From each of these stations we will imagine a line to be
drawn, terminating in the sun. Now it seems easy, by means of a
quadrant, to find the arch of a circle (in other words, the
angle) included between these lines terminating in the sun, and
the base formed by a right line drawn from one of these stations
to the other, which in this case is the length of the earth's
diameter. I have therefore now the three particulars required to
enable me to construct my triangle. And, according to the most
approved astronomical observations hitherto made, I have an
isosceles triangle, eight thousand miles broad at its base, and
ninety-five millions of miles in the length of each of the sides
reaching from the base to the apex.

It is however obvious to the most indifferent observer, that the
more any triangle, or other mathematical diagram, falls within
the limits which our senses can conveniently embrace, the more
securely, when our business is practical, and our purpose to
apply the result to external objects, can we rely on the accuracy
of our results. In a case therefore like the present, where the
base of our isosceles triangle is to the other two sides as eight
units to twelve thousand, it is impossible not to perceive that
it behoves us to be singularly diffident as to the conclusion at
which we have arrived, or rather it behoves us to take for
granted that we are not unlikely to fall into the most important
error. We have satisfied ourselves that the sides of the
triangle including the apex, do not form an angle, till they have
arrived at the extent of ninety-five millions of miles. How are
we sure that they do then? May not lines which have reached to
so amazing a length without meeting, be in reality parallel
lines? If an angle is never formed, there can be no result. The
whole question seems to be incommensurate to our faculties.

It being obvious that this was a very unsatisfactory scheme for
arriving at the knowledge desired, the celebrated Halley
suggested another method, in the year 1716, by an observation to
be taken at the time of the transit of Venus over the sun[50].

[50] Philosophical Transactions, Vol. XXIX, p. 454.

It was supposed that we were already pretty accurately acquainted
with the distance of the moon from the earth, it being so much
nearer to us, by observing its parallax, or the difference of its
place in the heavens as seen from the surface of the earth, from
that in which it would appear if seen from its centre[51]. But
the parallax of the sun is so exceedingly small, as scarcely to
afford the basis of a mathematical calculation[52]. The parallax
of Venus is however almost four times as great as that of the
sun; and there must therefore be a very sensible difference
between the times in which Venus may be seen passing over the sun
from different parts of the earth. It was on this account
apprehended, that the parallax of the sun, by means of
observations taken from different places at the time of the
transit of Venus in 1761 and 1769, might be ascertained with a
great degree of precision[53].

[51] Bonnycastle, Astronomy, 7th edition, p. 262, et seq.

[52] Ibid, p. 268.

[53] Phil. Transactions, Vol. XXIX, p. 457.

But the imperfectness of our instruments and means of observation
have no small tendency to baffle the ambition of man in these
curious investigations.

"The true quantity of the moon's parallax," says Bonnycastle,
"cannot be accurately determined by the methods ordinarily
resorted to, on account of the varying declination of the moon,
and the inconstancy of the horizontal refractions, which are
perpetually changing according to the state the atmosphere is in
at the time. For the moon continues but for a short time in the
equinoctial, and the refraction at a mean rate elevates her
apparent place near the horizon, half as much as her parallax
depresses it[54]."

[54] Astronomy, p. 265.

"It is well known that the parallax of the sun can never exceed
nine seconds, or the four-hundredth part of a degree[55]."
"Observations," says Halley, "made upon the vibrations of a
pendulum, to determine these exceedingly small angles, are not
sufficiently accurate to be depended upon; for by this method of
ascertaining the parallax, it will sometimes come out to be
nothing, or even negative; that is, the distance will either be
infinite, or greater than infinite, which is absurd. And, to
confess the truth, it is hardly possible for a person to
distinguish seconds with certainty by any instruments, however
skilfully they may be made; and therefore it is not to be
wondered at, that the excessive nicety of this matter should have
eluded the many ingenious endeavours of the most able
opetators[56].

[55] Ibid, p. 268.

[56] Phil. Transactions, Vol. XXIX, p. 456.

Such are the difficulties that beset the subject on every side.
It is for the impartial and dispassionate observers who have
mastered all the subtleties of the science, if such can be found,
to determine whether the remedies that have been resorted to to
obviate the above inaccuracies and their causes, have fulfilled
their end, and are not exposed to similar errors. But it would
be vain to expect the persons, who have "scorned delights, and
lived laborious days" to possess themselves of the mysteries of
astronomy, should be impartial and dispassionate, or be disposed
to confess, even to their own minds, that their researches were
useless, and their labours ended in nothing.

It is further worthy of our attention, that the instruments with
which we measure the distance of the earth from the sun and the
planets, are the very instruments which have been pronounced upon
as incompetent in measuring the heights of mountains[57]. In the
latter case therefore we have substituted a different mode for
arriving at the truth, which is supposed to be attended with
greater precision: but we have no substitute to which we can
resort, to correct the mistakes into which we may fall respecting
the heavenly bodies.

[57] See above, Essay XXI.

The result of the uncertainty which adheres to all astronomical
observations is such as might have been expected. Common readers
are only informed of the latest adjustment of the question, and
are therefore unavoidably led to believe that the distance of the
sun from the earth, ever since astronomy became entitled to the
name of a science, has by universal consent been recognised as
ninety-five millions of miles, or, as near as may be, twenty-four
thousand semi-diameters of the earth. But how does the case
really stand? Copernicus and Tycho Brahe held the distance to be
twelve hundred semi-diameters; Kepler, who is received to have
been perhaps the greatest astronomer that any age has produced,
puts it down as three thousand five hundred semi-diameters; since
his time, Riccioli as seven thousand; Hevelius as five thousand
two hundred and fifty[58]; some later astronomers, mentioned by
Halley, as fourteen thousand; and Halley himself as sixteen
thousand five hundred[59].

[58] They were about thirty and forty years younger than Kepler
respectively.

[59] Halley, apud Philosophical Transactions, Vol. XXIX, p. 455.

The doctrine of fluxions is likewise called in by the astronomers
in their attempts to ascertain the distance and magnitude of the
different celestial bodies which compose the solar system; and in
this way their conclusions become subject to all the difficulties
which Berkeley has alleged against that doctrine.

Kepler has also supplied us with another mode of arriving at the
distance and size of the sun and the planets: he has hazarded a
conjecture, that the squares of the times of the revolution of
the earth and the other planets are in proportion to the cubes of
their distances from the sun, their common centre; and, as by
observation we can arrive with tolerable certainty at a knowledge
of the times of their revolutions, we may from hence proceed to
the other matters we are desirous to ascertain. And that which
Kepler seemed, as by a divine inspiration, to hazard in the way
of conjecture, Newton professes to have demonstratively
established. But the demonstration of Newton has not been
considered as satisfactory by all men of science since his time.

Thus far however we proceed as we may, respecting our
propositions on the subject of the solar system. But, beyond
this, all science, real or pretended, deserts us. We have no
method for measuring angles, which can be applied to the fixed
stars; and we know nothing of any revolutions they perform. All
here therefore seems gratuitous: we reason from certain alleged
analogies; and we can do no more.

Huygens endeavoured to ascertain something on the subject, by
making the aperture of a telescope so small, that the sun should
appear through it no larger than Sirius, which he found to be
only in the proportion of 1 to 27,664 times his diameter, as seen
by the naked eye. Hence, supposing Sirius to be a globe of the
same magnitude as the sun, it must be 27,664 times as distant
from us as the sun, in other words, at a distance so considerable
as to equal 345 million diameters of the earth[60]. Every one
must feel on how slender a thread this conclusion is suspended.

[60] Encyclopaedia Londinensis, Vol. 11, p. 407.

And yet, from this small postulate, the astronomers proceed to
deduce the most astounding conclusions. They tell us, that the
distance of the nearest fixed star from the earth is at least
7,600,000,000,000 miles, and of another they name, not less than
38 millions of millions of miles. A cannon-ball therefore,
proceeding at the rate of about twenty miles in a minute would be
760,000 years in passing from us to the nearest fixed star, and
3,800,000 in passing to the second star of which we speak.
Huygens accordingly concluded, that it was not impossible, that
there might be stars at such inconceivable distances from us,
that their light has not yet reached the earth since its
creation[61].

[61] Ibid, p. 408.

The received system of the universe, founded upon these so called
discoveries, is that each of the stars is a sun, having planets
and comets revolving round it, as our sun has the earth and other
planets revolving round him. It has been found also by the
successive observations of astronomers, that a star now and then
is totally lost, and that a new star makes its appearance which
had never been remarked before: and this they explain into the
creation of a new system from time to time by the Almighty author
of the universe, and the destruction of an old system worn out
with age[62]. We must also remember the power of attraction
every where diffused through infinite space, by means of which,
as Herschel assures us, in great length of time a nebula, or
cluster of stars, may be formed, while the projectile force they
received in the beginning may prevent them from all coming
together, at least for millions of ages. Some of these nebulae,
he adds, cannot well be supposed to be at a less distance from us
than six or eight thousand times the distance of Sirius[63].
Kepler however denies that each star, of those which distinctly
present themselves to our sight, can have its system of planets
as our sun has, and considers them as all fixed in the same
surface or sphere; since, if one of them were twice or thrice as
remote as another, it would, supposing their real magnitudes to
be equal, appear to be twice or thrice as small, whereas there is
not in their apparent magnitudes the slightest difference[64].

[62] Encycl. Lond. Vol. II, p. 411.

[63] Ibid, p. 348.

[64] Ibid, p. 411.

Certainly the astronomers are a very fortunate and privileged
race of men, who talk to us in this oracular way of "the unseen
things of God from the creation of the world," hanging up their
conclusions upon invisible hooks, while the rest of mankind sit
listening gravely to their responses, and unreservedly
"acknowledging that their science is the most sublime, the most
interesting, and the most useful of all the sciences cultivated
by man[65]."

[65] Ferguson, Astronomy, Section 1.

We have a sensation, which we call the sensation of distance. It
comes to us from our sight and our other senses. It does not
come immediately by the organ of sight. It has been proved, that
the objects we see, previously to the comparison and correction
of the reports of the organ of sight with those of the other
senses, do not suggest to us the idea of distance, but that on
the contrary whatever we see seems to touch the eye, even as the
objects of the sense of feeling touch the skin.

But, in proportion as we compare the impressions made upon our
organs of sight with the impressions made on the other senses, we
come gradually to connect with the objects we see the idea of
distance. I put out my hand, and find at first that an object of
my sense of sight is not within the reach of my hand. I put out
my hand farther, or by walking advance my body in the direction
of the object, and I am enabled to reach it. From smaller
experiments I proceed to greater. I walk towards a tree or a
building, the figure of which presents itself to my eye, but
which I find upon trial to have been far from me. I travel
towards a place that I cannot see, but which I am told lies in a
certain direction. I arrive at the place. It is thus, that by
repeated experiments I acquire the idea of remote distances.

To confine ourselves however to the question of objects, which
without change of place I can discover by the sense of sight. I
can see a town, a tower, a mountain at a considerable distance.
Let us suppose that the limit of my sight, so far as relates to
objects on the earth, is one hundred miles. I can travel towards
such an object, and thus ascertain by means of my other senses
what is its real distance. I can also employ certain
instruments, invented by man, to measure heights, suppose of a
tower, and, by experiments made in ways independent of these
instruments, verify or otherwise the report of these instruments.

The height of the Monument of London is something more than two
hundred feet. Other elevations, the produce of human labour, are
considerably higher. It is in the nature of the mind, that we
conclude from the observation that we have verified, to the
accuracy of another, bearing a striking analogy to the former,
that we have not verified. But analogy has its limits. Is it of
irresistible certainty, or is it in fact to be considered as
approaching to certainty, because we have verified an observation
extending to several hundred feet, that an observation extending
to ninety-five millions of miles, or to the incredible distances
of which Herschel so familiarly talks, is to be treated as a
fact, or laid down as a principle in science? Is it reasonable
to consider two propositions as analogous, when the thing
affirmed in the one is in dimension many million times as great
as the thing affirmed in the other? The experience we have had
as to the truth of the smaller, does it authorise us to consider
the larger as unquestionable? That which I see with a bay of the
sea or a wide river between, though it may appear very like
something with which I am familiar at home, do I immediately
affirm it to be of the same species and nature, or do I not
regard it with a certain degree of scepticism, especially if,
along with the resemblance in some points, it differs
essentially, as for example in magnitude, in other points? We
have a sensation, and we enquire into its cause. This is always
a question of some uncertainty. Is its cause something of
absolute and substantive existence without me, or is it not? Is
its cause something of the very same nature, as the thing that
gave me a similar sensation in a matter of comparatively a pigmy
and diminutive extension?

All these questions an untrained and inquisitive mind will ask
itself in the propositions of astronomy. We must believe or not,
as we think proper or reasonable. We have no way of verifying
the propositions by the trial of our senses. There they lie, to
be received by us in the construction that first suggests itself
to us, or not. They are something like an agreeable imagination
or fiction: and a sober observer, in cold blood, will be
disposed deliberately to weigh both sides of the question, and to
judge whether the probability lies in favour of the actual
affirmation of the millions of millions of miles, and the other
incredible propositions of the travelling of light, and the rest,
which even the most cautious and sceptical of the retainers of
modern astronomy, find themselves compelled to receive.

But I shall be told, that the results of our observations of the
distances of the heavenly bodies are unvaried. We have measured
the distances and other phenomena of the sun, the moon, Mercury,
Venus, Mars, Jupiter, Saturn, and their satellites, and they all
fall into a grand system, so as to convey to every unprejudiced
mind the conviction that this system is the truth itself. If we
look at them day after day, and year after year, we see them for
ever the same, and performing the same divine harmony.
Successive astronomers in different ages and countries have
observed the celestial orbs, and swept the heavens, and for ever
bring us back the same story of the number, the dimensions, the
distances, and the arrangement of the heavenly bodies which form
the subject of astronomical science.

This we have seen indeed not to be exactly the case. But, if it
were, it would go a very little way towards proving the point it
was brought to prove. It would shew that, the sensations and
results being similar, the causes of those results must be
similar to each other, but it would not shew that the causes were
similar to the sensations produced. Thus, in the sensations
which belong to taste, smell, sound, colour, and to those of heat
and cold, there is all the uniformity which would arise, when the
real external causes bore the most exact similitude to the
perceptions they generate; and yet it is now universally
confessed that tastes, scents, sounds, colours, and heat and cold
do not exist out of ourselves. All that we are entitled
therefore to conclude as to the magnitudes and distances of the
heavenly bodies, is, that the causes of our sensations and
perceptions, whatever they are, are not less uniform than the
sensations and perceptions themselves.

It is further alleged, that we calculate eclipses, and register
the various phenomena of the heavenly bodies. Thales predicted
an eclipse of the sun, which took place nearly six hundred years
before the Christian era. The Babylonians, the Persians, the
Hindoos, and the Chinese early turned their attention to
astronomy. Many of their observations were accurately recorded;
and their tables extend to a period of three thousand years
before the birth of Christ. Does not all this strongly argue the
solidity of the science to which they belong? Who, after this,
will have the presumption to question, that the men who profess
astronomy proceed on real grounds, and have a profound knowledge
of these things, which at first sight might appear to be set at a
distance so far removed from our ken?

The answer to this is easy. I believe in all the astronomy that
was believed by Thales. I do not question the statements
relative to the heavenly bodies that were delivered by the wise
men of the East. But the supposed discoveries that were made in
the eighteenth, and even in the latter part of the seventeenth
century, purporting to ascertain the precise distance of the sun,
the planets, and even of the fixed stars, are matters entirely
distinct from this.

Among the earliest astronomers of Greece were Thales,
Anaximander, Anaximenes and Anaxagoras. Thales, we are told,
held that the earth is a sphere or globe, Anaximenes that it is
like a round, flat table; Anaximander that the sun is like a
chariot-wheel, and is twenty-eight times larger than the earth.
Anaxagoras was put in prison for affirming that the sun was by
many degrees larger than the whole Peloponnesus[66]. Kepler is
of opinion that all the stars are at an equal distance from us,
and are fixed in the same surface or sphere.

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