228 THE GROUNDWORK OF SCIENCE

of truths, the perception of all of which is indispensably

necessary for science. These are : (i) certain general

principles ; (2) certain particular facts ; and (3) certain

processes of reasoning.

Without a knowledge of certain general principles we

could not argue ; without a knowledge of certain facts all

our reasoning would merely concern abstract ideas ; and

without a reference to concrete reality, and without some

criterion of valid reasoning, we could never arrive at any

conclusion or discover and explicitly recognize implicit

truths, no inferences could be deduced, and no advance in

science could be consequently attained.

We will select from the category of particular facts one

which may serve as a solid foundation and starting-point

towards a pursuit of our object.

Let us suppose that certain definite observations and

experiments have been carried on such, e.g., as those

which were performed by the late M. Pasteur with a view

to the treatment of rabies. Now there is one supremely

important truth which is implied in our certainty as to

the result of any such experiment, whatever that result

may be. Unless we can be sure that it was we who both

began the experiment and also witnessed its conclusion

that there had been no change in our personality while

experimenting such conclusion could not be confidently

relied on by us, as we have before pointed out.* The most

fundamental of all facts for our purpose is the fact of our

continuous personal existence.

Now, of course, no one is so mad as to deny that he

knows his existence at the moment he thinks about it.

We have already noticed the absolute certainty we have

about any feeling while we feel it ; and as nothing can

feel which does not exist, the certainty about the existence

* See ante, p. 101.

of truths, the perception of all of which is indispensably

necessary for science. These are : (i) certain general

principles ; (2) certain particular facts ; and (3) certain

processes of reasoning.

Without a knowledge of certain general principles we

could not argue ; without a knowledge of certain facts all

our reasoning would merely concern abstract ideas ; and

without a reference to concrete reality, and without some

criterion of valid reasoning, we could never arrive at any

conclusion or discover and explicitly recognize implicit

truths, no inferences could be deduced, and no advance in

science could be consequently attained.

We will select from the category of particular facts one

which may serve as a solid foundation and starting-point

towards a pursuit of our object.

Let us suppose that certain definite observations and

experiments have been carried on such, e.g., as those

which were performed by the late M. Pasteur with a view

to the treatment of rabies. Now there is one supremely

important truth which is implied in our certainty as to

the result of any such experiment, whatever that result

may be. Unless we can be sure that it was we who both

began the experiment and also witnessed its conclusion

that there had been no change in our personality while

experimenting such conclusion could not be confidently

relied on by us, as we have before pointed out.* The most

fundamental of all facts for our purpose is the fact of our

continuous personal existence.

Now, of course, no one is so mad as to deny that he

knows his existence at the moment he thinks about it.

We have already noticed the absolute certainty we have

about any feeling while we feel it ; and as nothing can

feel which does not exist, the certainty about the existence

* See ante, p. 101.