be simple.

It is scarcely necessary in view of the foregoing to add that the data
of science are not "sense-data," if by sense-data be meant data which
are the result of the operations of sense organs alone. Data are as much
or more the result of operations, first, of the motor system of the
scientist's own organism, and second, of all of the machinery of his
laboratory which he calls to his aid. Whether named after the way they
are obtained, or after the way they are used, data are quite as much
"motor" as "sense." Nor, on the other hand, are there any purely
intellectual data--not even for the mathematician. Some mathematicians
may insist that their symbols and diagrams are merely stimuli to the
platonic operation of pure and given universals. But until mathematics
can get on without these symbols or any substitutes the intuitionist in
mathematics will continue to have his say.

Wherever the discontinuity between logical operations and their acts
persists, all the difficulties with data have their correlative
difficulties with hypotheses. In Mill's logic the account of the origin
of hypotheses oscillates between the view that they are happy guesses
of a mind composed of states of consciousness, and the view that they
are "found in the facts" or are "impressed on the mind by the facts."
The miracle of relevancy required in the first position drives the
theory to the second. And the tautologous, useless nature of the
hypothesis in the second forces the theory back to the first view. In
this predicament, little wonder Mill finds that the easiest way out is
to make hypotheses "auxiliary" and not indigenous to inference. But this
exclusion of hypotheses as essential leaves his account of inference to
oscillate between the association of particulars of nominalism and
scholastic formalism, from both of which Mill, with the dignified zeal
of a prophet, set out to rescue logic.

Mill's rejection of hypotheses formed by a mind whose operations have no
discoverable continuity with the operations of things, or by things
whose actions are independent of the operations of ideas, is forever
sound. But his acceptance of the discontinuity between the acts of
knowing and the operation of things, and the conclusion that these two
conceptions of the origin and nature of hypotheses are the only
alternatives, were the source of most of his difficulties.

III

The efforts of classic empiricism at the reform of logic have long been