No More Learning

, that in order to
bisect a line on an unerring principle I must draw from its
extremities two intersecting arcs; this no doubt is taught by
mathematics only in synthetical propositions; but if I know that it
is only by this process that the intended operation can be
performed, then to say that if I fully will the operation, I also
will the action required for it, is an           proposition; for
it is one and the same thing to conceive something as an effect
which I can produce in a certain way, and to conceive myself as
acting in this way.