applying
such general conceptions as were most satisfying to the reasons of their
respective authors. But they contributed nothing whatsoever to a
practical familiarity with the natural course of events, in this case
the times and places of the planets and the tides. Hence they have not
been used in the building of science. In our own day investigators have
become conscious of their motive, and do not wait for historical
selection to exclude powers and reasons from their province. They
deliberately seek to formulate exact descriptions. To this end they
employ symbols that shall serve to identify the terms of nature, and
formulas that shall define their systematic relationship. These systems
must be exact, or deductions cannot be made from them. Hence they tend
ultimately to assume a mathematical form of expression.

[Sidenote: Space, Time, and Prediction.]

Sect. 47. But science tends to employ for these systems only such
conceptions as relate to _prediction_; and of these the most fundamental
are _space_ and _time_. The first science to establish its method was
the science of astronomy, where measurement and computation in terms of
space and time were the most obvious means of description; and the
general application of the method of astronomy by Galileo and Newton, or
the development of mechanics, is the most important factor in the
establishment of modern science upon a permanent working basis. The
persistence of the term _cause_, testifies to the fact that science is
primarily concerned with the determination of _events_. Its definitions
of objects are means of identification, while its laws are dynamical,
_i. e._, have reference to the conditions under which these objects
arise. Thus the chemist may know less about the properties of water than
the poet; but he is pre-eminently skilled in its production from
elements, and understands similarly the compounds into which it may
enter. Now the general conditions of all anticipation, whereby it
becomes exact and verifiable, are spacial and temporal. A predictable
event must be assigned to what is here now, or there now; or what is
here then, or there then. An experimentally verifiable system must
contain space-time variables, for which can be substituted the here and
now of the experimenter's immediate experience. Hence science deals
primarily with calculable places and moments. The mechanical theory of
nature owes its success to a union of space and time through its