excellent and delicate of those powers. In old age the mind gradually
withers; and as it grew and was strengthened with the body, so does
it together with the body sink into decrepitude. Assuredly these
are convincing evidences that so soon as the organs of the body
are subjected to the laws of inanimate matter, sensation, and
perception, and apprehension, are at an end. It is probable that
what we call thought is not an actual being, but no more than the
relation between certain parts of that infinitely varied mass,
of which the rest of the universe is composed, and which ceases
to exist so soon as those parts change their position with regard
to each other. Thus colour, and sound, and taste, and odour exist
only relatively. But let thought be considered as some peculiar
substance, which permeates, and is the cause of, the animation of
living beings. Why should that substance be assumed to be something
essentially distinct from all others, and exempt from subjection
to those laws from which no other substance is exempt? It differs,
indeed, from all other substances, as electricity, and light, and
magnetism, and the constituent parts of air and earth, severally
differ from all others. Each of these is subject to change and
to decay, and to conversion into other forms. Yet the difference
between light and earth is scarcely greater than that which exists
between life, or thought, and fire. The difference between the two
former was never alleged as an argument for the eternal permanence
of either, in that form under which they first might offer themselves
to our notice. Why should the difference between the two latter
substances be an argument for the prolongation of the existence
of one and not the other, when the existence of both has arrived
at their apparent termination? To say that fire exists without
manifesting any of the properties of fire, such as light, heat,
etc., or that the principle of life exists without consciousness,