98 THE GROUNDWORK OF SCIENCE

Thus for the astronomer, the earth's annual revolution

round the sun, its daily revolution round its own axis and

the coinciding of these two revolutions in the case of the

moon, are matters of absolute certainty. No geologist

entertains the slighest doubt that the earth's crust is largely

composed of strata which have been in past ages deposited

from water.

No zoologist can doubt that the transitory stages most

of the higher animals go through in passing from their

embryonic to their adult condition, bear a general resem-

blance to permanent adult conditions of other animals of

lower types of organization. It is in science, as it is in

matters of every-day life, there are a multitude of facts as

to which no man in his senses can entertain any doubt.

Though we are for the most part content to act on reasonable

probabilities, yet certainty attends us at every turn. If

we meet a friend in the street going away from home,

we know that we shall not find him if we go straight to

his house. If we find on returning to our library that a

window, which we had carefully closed before starting, is

open, we are quite sure that someone must have opened it.

Such certainties about ordinary and scientific matters are

quite beyond the reach of reasonable doubt, and it is very

necessary, for our purpose here, to recognize that such is

the case.

The methods of science clearly imply a conviction on the

part of those who follow them that there really is such a

thing as legitimate certainty.

If such were not the case, there could be no true science

oi any kind. Blind disbelief would be as fatal to science

as blind belief, and healthy and firm convictions must follow

the presence of sufficient evidence, otherwise the progress

of science would be fatally arrested. It is necessary, then,

distinctly to recognize that there is such a thing as legitimate

Thus for the astronomer, the earth's annual revolution

round the sun, its daily revolution round its own axis and

the coinciding of these two revolutions in the case of the

moon, are matters of absolute certainty. No geologist

entertains the slighest doubt that the earth's crust is largely

composed of strata which have been in past ages deposited

from water.

No zoologist can doubt that the transitory stages most

of the higher animals go through in passing from their

embryonic to their adult condition, bear a general resem-

blance to permanent adult conditions of other animals of

lower types of organization. It is in science, as it is in

matters of every-day life, there are a multitude of facts as

to which no man in his senses can entertain any doubt.

Though we are for the most part content to act on reasonable

probabilities, yet certainty attends us at every turn. If

we meet a friend in the street going away from home,

we know that we shall not find him if we go straight to

his house. If we find on returning to our library that a

window, which we had carefully closed before starting, is

open, we are quite sure that someone must have opened it.

Such certainties about ordinary and scientific matters are

quite beyond the reach of reasonable doubt, and it is very

necessary, for our purpose here, to recognize that such is

the case.

The methods of science clearly imply a conviction on the

part of those who follow them that there really is such a

thing as legitimate certainty.

If such were not the case, there could be no true science

oi any kind. Blind disbelief would be as fatal to science

as blind belief, and healthy and firm convictions must follow

the presence of sufficient evidence, otherwise the progress

of science would be fatally arrested. It is necessary, then,

distinctly to recognize that there is such a thing as legitimate