Th e word “mutability” (13) most nearly means
(a) variability
(b) silence
(c) persistence
(d) life
(e) death
passage 1. charles darwin, on the origin of species
i have now recapitulated the chief facts and considerations which have thoroughly
convinced me that species have been modifi ed, during a long course of
descent, by the preservation or the natural selection of many successive slight
favourable variations. i cannot believe that a false theory would explain, as it seems
to me that the theory of natural selection does explain, the several large classes
of facts above specifi ed. i see no good reason why the views given in this volume
should shock the religious feelings of any one. a celebrated author and divine has
written to me that “he has gradually learnt to see that it is just as noble a conception
of the deity to believe that he created a few original forms capable of selfdevelopment
into other and needful forms, as to believe that he required a fresh
act of creation to supply the voids caused by the action of his laws.”
why, it may be asked, have all the most eminent living naturalists and geologists
rejected this view of the mutability of species? it cannot be asserted that
organic beings in a state of nature are subject to no variation; it cannot be proved
that the amount of variation in the course of long ages is a limited quantity; no
clear distinction has been, or can be, drawn between species and well-marked varieties.
it cannot be maintained that species when intercrossed are invariably sterile,
and varieties invariably fertile; or that sterility is a special endowment and sign of
creation. th e belief that species were immutable productions was almost unavoidable
as long as the history of the world was thought to be of short duration; and
now that we have acquired some idea of the lapse of time, we are too apt to assume,
without proof, that the geological record is so perfect that it would have aff orded
us plain evidence of the mutation of species, if they had undergone mutation.
but the chief cause of our natural unwillingness to admit that one species has
given birth to other and distinct species, is that we are always slow in admitting
any great change of which we do not see the intermediate steps. th e diffi culty is
the same as that felt by so many geologists, when lyell fi rst insisted that long lines
of inland cliff s had been formed, and great valleys excavated, by the slow action of
the coast-waves. th e mind cannot possibly grasp the full meaning of the term of a
hundred million years; it cannot add up and perceive the full eff ects of many slight
variations, accumulated during an almost infi nite number of generations.