half of 10, is a false proposition, and can never be distinctly
conceived. But that Caesar, or the angel Gabriel, or any being never
existed, may be a false proposition, but still is perfectly conceivable,
and implies no contradiction.

The existence, therefore, of any being can only be proved by arguments
from its cause or its effect; and these arguments are founded entirely
on experience. If we reason _a priori_, anything may appear able to
produce anything. The falling of a pebble may, for aught we know,
extinguish the sun; or the wish of a man control the planets in their
orbits. It is only experience, which teaches us the nature and bounds of
cause and effect, and enables us to infer the existence of one object
from that of another[34]. Such is the foundation of moral reasoning,
which forms the greater part of human knowledge, and is the source of
all human action and behaviour.

[34] That impious maxim of the ancient philosophy, _Ex nihilo,
nihil fit_, by which the creation of matter was excluded,
ceases to be a maxim, according to this philosophy. Not only the
will of the supreme Being may create matter; but, for aught we
know _a priori_, the will of any other being might create it,
or any other cause, that the most whimsical imagination
can assign.

Moral reasonings are either concerning particular or general facts. All
deliberations in life regard the former; as also all disquisitions in
history, chronology, geography, and astronomy.

The sciences, which treat of general facts, are politics, natural
philosophy, physic, chemistry, &c. where the qualities, causes and