96 THE GROUNDWORK OF SCIENCE

There is hardly need to remind any reader of this book

that the " method of agreement " is necessarily uncertain,

because one effect may have several causes ; but this defect

does not apply to " the joint method of agreement and

difference."

The idea as to what may be the cause of any effect is

generally suggested by analogy, or resemblance known, or

suspected, to exist between causes and effects thought to be

similar to the case investigated ; and, of course, a cause will,

as a rule, be the more easily discovered the greater the

number of instances of the supposed effect we examine.

A suspected cause may be tested by allowing it to operate

in circumstances of less complication, to see whether the

effect will still be produced. This is, of course, one important

instance of carrying on scientific experiments. The process

of seeking out analogies and resemblances wisely is perhaps

the special characteristic of a sagacious man of science. The

process of constructing carefully thought out hypotheses, and

then skilfully and accurately submitting them to fitting tests

for verification, is the method by which the greatest scientific

advances have been made during the last three centuries ;

although it must be admitted that much time and effort

have been wasted by the frequent emission of careless and

ill-considered speculations.

The foregoing observations with respect to the methods of

science may suffice, because our purpose in referring to, and

briefly noting them in the most general terms, has not been

for their own sake. We assume that most of our readers

already know as much as we could tell them with respect

to the methods of science generally, and the details of such

methods with respect to those sciences with which they are

best acquainted.

Our purpose in devoting this chapter to a general view of

the methods of science has had special reference as every

There is hardly need to remind any reader of this book

that the " method of agreement " is necessarily uncertain,

because one effect may have several causes ; but this defect

does not apply to " the joint method of agreement and

difference."

The idea as to what may be the cause of any effect is

generally suggested by analogy, or resemblance known, or

suspected, to exist between causes and effects thought to be

similar to the case investigated ; and, of course, a cause will,

as a rule, be the more easily discovered the greater the

number of instances of the supposed effect we examine.

A suspected cause may be tested by allowing it to operate

in circumstances of less complication, to see whether the

effect will still be produced. This is, of course, one important

instance of carrying on scientific experiments. The process

of seeking out analogies and resemblances wisely is perhaps

the special characteristic of a sagacious man of science. The

process of constructing carefully thought out hypotheses, and

then skilfully and accurately submitting them to fitting tests

for verification, is the method by which the greatest scientific

advances have been made during the last three centuries ;

although it must be admitted that much time and effort

have been wasted by the frequent emission of careless and

ill-considered speculations.

The foregoing observations with respect to the methods of

science may suffice, because our purpose in referring to, and

briefly noting them in the most general terms, has not been

for their own sake. We assume that most of our readers

already know as much as we could tell them with respect

to the methods of science generally, and the details of such

methods with respect to those sciences with which they are

best acquainted.

Our purpose in devoting this chapter to a general view of

the methods of science has had special reference as every