not hang together in any local contiguity. To construct a chart of the
world is a difficult feat of synthetic imagination, not to be performed
without speculative boldness and a heroic insensibility to the claims of
fancy. Even now most people live without topographical ideas and have no
clear conception of the spatial relations that keep together the world
in which they move. They feel their daily way about like animals,
following a habitual scent, without dominating the range of their
instinctive wanderings. Reality is rather a story to them than a system
of objects and forces, nor would they think themselves mad if at any
time their experience should wander into a fourth dimension. Vague
dramatic and moral laws, when they find any casual application, seem to
such dreaming minds more notable truths, deeper revelations of
efficacious reality, than the mechanical necessities of the case, which
they scarcely conceive of; and in this primordial prejudice they are
confirmed by superstitious affinities often surviving in their religion
and philosophy. In the midst of cities and affairs they are like
landsmen at sea, incapable of an intellectual conception of their
position: nor have they any complete confidence in their principles of
navigation. They know the logarithms by rote merely, and if they reflect
are reduced to a stupid wonder and only half believe they are in a known
universe or will ever reach an earthly port. It would not require
superhuman eloquence in some prophetic passenger to persuade them to
throw compass and quadrant overboard and steer enthusiastically for El
Dorado. The theory of navigation is essentially as speculative as that
of salvation, only it has survived more experiences of the judgment and
repeatedly brought those who trust in it to their promised land.

[Sidenote: Its unity ideal and discoverable only by steady thought.]

The theory that all real objects and places lie together in one even and
homogeneous space, conceived as similar in its constitution to the parts
of extension of which we have immediate intuition, is a theory of the
greatest practical importance and validity. By its light we carry on all
our affairs, and the success of our action while we rely upon it is the
best proof of its truth. The imaginative parsimony and discipline which
such a theory involves are balanced by the immense extension and
certitude it gives to knowledge. It is at once an act of allegiance to
nature and a