Introduction 21 
be sure that it is not the work of one who is unable to 
understand how anything can possibly go right unless he 
sees to it himself. Nature works departmentally and by 
way of leaving details to subordinates. But though those 
who see nature thus do indeed deny design of the prescient- 
from-all-eternity order, they in no way impugn a method 
which is far more in accord with all that we commonly 
think of as design. A design which is as incredible as that 
a ewe should give birth to a lion becomes of a piece with all 
that we observe most frequently if it be regarded rather 
as an aggregation of many small steps than as a single large 
one. This principle is very simple, but it seems rather 
difficult to understand. It has taken several generations 
before people would admit it as regards organism even after 
it was pointed out to them, and those who saw it as regards 
organism still failed to understand it as regards design ; 
an inexorable “ Thus far shalt thou go and no farther” 
barred them from fruition of the harvest they should have 
been the first to reap. The very men who most insisted 
that specific difference was the accumulation of differences 
so minute as to be often hardly, if at all, perceptible, could 
not see that the striking and baffling phenomena of design 
in connection with organism admitted of exactly the same 
solution as the riddle of organic development, and should 
be seen not as a result reached per saltum, but as an accumu- 
lation of small steps or leaps in a given direction. It was 
as though those who had insisted on the derivation of all 
forms of the steam-engine from the common kettle, and 
who saw that this stands in much the same relations to 
the engines, we will say, of the Great Eastern steamship 
as the amceba to man, were to declare that the Great 
Eastern engines were not designed at all, on the ground 
that no one in the early kettle days had foreseen so great a 
future development, and were unable to understand that 
a piecemeal solvitur ambulando design is more omnipresent, 
all-seeing, and all-searching, and hence more truly in the 
