reader, for the frequent use of the word Idea, which he
will find in the following Treatise. It being that term which, I think,
serves best to stand for whatsoever is the object of the understanding,
when a man thinks. I have used it to express whatever is meant by
Phantasm, Notion, Species, OR WHATEVER IT IS, which the mind can be
employed about in thinking; and I could not avoid frequently using it."
Dr. REID follows nearly in the same track:--"It is a fundamental
principle of the Ideal system, that every object of thought, must be an
_impression_ or an _Idea_, that is, a _faint copy_ of some preceding
impression."--_Inquiry into the Human Mind on the Principles of Common
Sense_, 1765, p. 41.

The doctrine of Innate Ideas having been deservedly exploded, it follows
that these Ideas must be derived from our intercourse with the world we
inhabit. For this purpose we are furnished with five senses, from each
of which we obtain a separate and different kind of intelligence, which
is denominated Perception. The perceptions of the Eye, under an
attentive inspection, leave on the Sensorium a phantasm or Idea of the
object, a vivid memorial of that which has been perceived; but the
other senses do not convey any similar phantasm.[1] The doctrine of
Ideas appears to have been countenanced, and reconciled under all its
difficulties, from a presumed spiritual operation and guidance in the
act of thinking, and especially to an implacable aversion to any
explanation that might be deemed to savour of _materialism_. This term,
the denunciation of the pious, the convenient obloquy of the ignorant,
being equal in its sweeping persecution, to the horrible word craven,
demands a brief and modest exposition. That we exist in a material
world, will scarcely be denied, and it is a fair inference, that the
annihilation of matter would involve our globe and its inhabitants in
equal destruction. Of this matter, the concentrated power of man cannot
create nor exterminate a single atom. The human body is a material
fabric: the brain and nerves, together with those delicate organs that
are the instruments of our perceptions,--whereby we receive light,
detect fragrance, apprehend sounds, relish viands, and enjoy the
gratifications of contact, are all of material structure: and when that
state, called Death, has ensued, their offices cease, and they undergo
the decompositions to which all animal matter is subjected.

The _Capacities_, by which w