Immediate Inference.
Probably the simplest of all forms of inference is that which has been called Immediate Inference, because it can be performed upon a single proposition. It consists in joining an adjective, or other qualifying clause of the same nature, to both sides of an identity, and asserting the equivalence of the terms thus produced. For instance, since
Conductors of electricity = Non-electrics,
it follows that
Liquid conductors of electricity = Liquid non-electrics.
If we suppose that
Plants = Bodies decomposing carbonic acid,
it follows that
Microscopic plants = Microscopic bodies decomposing carbonic acid.
In general terms, from the identity