Mathematics is of narrower scope. What it studies is no longer "real
being as such," but only real being in so far as it exhibits number and
geometrical form. Since Aristotle holds the view that number and figure
only exist as determinations of objects given in perception (though by a
convenient fiction the mathematician treats of them in abstraction from
the perceived objects which they qualify), he marks the difference
between Mathematics and First Philosophy by saying that "whereas the
objects of First Philosophy are separate from matter and devoid of
motion, those of Mathematics, though incapable of motion, have no
separable existence but are inherent in matter." Physics is concerned
with the study of objects which are both material and capable of motion.
Thus the principle of the distinction is the presence or absence of
initial restrictions of the range of the different branches of Science.
First Philosophy has the widest range, since its contemplation covers
the whole ground of the real and knowable; Physics the narrowest,
because it is confined to a "universe of discourse" restricted by the
double qualification that its members are all material and capable of
displacement. Mathematics holds an intermediate position, since in it,
one of these qualifications is removed, but the other still remains, for
the geometer’s figures are boundaries and limits of sensible bodies, and
the arithmetician’s numbers properties of collections of concrete
objects. It follows also that the initial axioms or postulates of
Mathematics form a less simple system than those of First Philosophy,
and those of Physics than those of Mathematics. Mathematics requires as
initial assumptions not only those which hold good for _all_ thought,
but certain other special axioms which are only valid and significant
for the realm of figure and number; Physics requires yet further axioms
which are only applicable to "what is in motion." This is why, though
the three disciplines are treated as distinct, they are not strictly
co-ordinate, and "First Philosophy," though "first," is only _prima
inter pares_.
We thus get the following diagrammatic scheme of the classification of
sciences:--
Science
|
+−−−−−−−−−−−+−−−−−−−−−−−−+
| |
Theoretical Practical
|
+−−−+−−−−−−−−−+−−−−−−−−−−−+
| | |
First Philosophy Mathe− Physics
or matics
Theology