The Method by which the Causes of the Present and Past Conditions of Organic Nature Are to Be Disco | Page 9

verified. It is
in these matters as in the commonest affairs of practical life: the guess
of the fool will be folly, while the guess of the wise man will contain
wisdom. In all cases, you see that the value of the result depends on the
patience and faithfulness with which the investigator applies to his
hypothesis every possible kind of verification.
I dare say I may have to return to this point by-and-by; but having dealt
thus far with our logical methods, I must now turn to something which,
perhaps, you may consider more interesting, or, at any rate, more
tangible. But in reality there are but few things that can be more
important for you to understand than the mental processes and the
means by which we obtain scientific conclusions and theories.1 Having

granted that the inquiry is a proper one, and having determined on the
nature of the methods we are to pursue and which only can lead to
success, I must now turn to the consideration of our knowledge of the
nature of the processes which have resulted in the present condition of
organic nature.
Here, let me say at once, lest some of you misunderstand me, that I
have extremely little to report. The question of how the present
condition of organic nature came about, resolves itself into two
questions. The first is: How has organic or living matter commenced its
existence? And the second is: How has it been perpetuated? On the
second question I shall have more to say hereafter. But on the first one,
what I now have to say will be for the most part of a negative character.
If you consider what kind of evidence we can have upon this matter, it
will resolve itself into two kinds. We may have historical evidence and
we may have experimental evidence. It is, for example, conceivable,
that inasmuch as the hardened mud which forms a considerable portion
of the thickness of the earth's crust contains faithful records of the past
forms of life, and inasmuch as these differ more and more as we go
further down,--it is possible and conceivable that we might come to
some particular bed or stratum which should contain the remains of
those creatures with which organic life began upon the earth. And if we
did so, and if such forms of organic life were preservable, we should
have what I would call historical evidence of the mode in which
organic life began upon this planet. Many persons will tell you, and
indeed you will find it stated in many works on geology, that this has
been done, and that we really possess such a record; there are some
who imagine that the earliest forms of life of which we have as yet
discovered any record, are in truth the forms in which animal life began
upon the globe. The grounds on which they base that supposition are
these:--That if you go through the enormous thickness of the earth's
crust and get down to the older rocks, the higher vertebrate
animals--the quadrupeds, birds, and fishes--cease to be found; beneath
them you find only the invertebrate animals; and in the deepest and
lowest rocks those remains become scantier and scantier, not in any
very gradual progression, however, until, at length, in what are
supposed to be the oldest rocks, the animal remains which are found are
almost always confined to four forms--'Oldhamia', whose precise

nature is not known, whether plant or animal; 'Lingula', a kind of
mollusc; 'Trilobites', a crustacean animal, having the same essential
plan of construction, though differing in many details from a lobster or
crab; and Hymenocaris, which is also a crustacean. So that you have all
the 'Fauna' reduced, at this period, to four forms: one a kind of animal
or plant that we know nothing about, and three undoubted animals--two
crustaceans and one mollusc.
I think, considering the organization of these mollusca and crustacea,
and looking at their very complex nature, that it does indeed require a
very strong imagination to conceive that these were the first created of
all living things. And you must take into consideration the fact that we
have not the slightest proof that these which we call the oldest beds are
really so: I repeat, we have not the slightest proof of it. When you find
in some places that in an enormous thickness of rocks there are but very
scanty traces of life, or absolutely none at all; and that in other parts of
the world rocks of the very same formation are crowded with the
records of living forms, I think it is impossible to place any reliance on
the supposition, or to feel oneself justified in supposing that these are
the forms in which life first commenced. I