Deduction is the mental process of forming conclusions based on premises.
The conclusions must follow directly and necessarily from the premises.
An example is the premises: the house is white; I own the house.
From this we can conclude that I own a white house.
Deduction is useful in combining knowledge to form new knowledge.
It is a form of analysis that creates new insights.
Deduction is an act of integration.
It combines two related premises, and identifies the new integration.
The new idea must obey the Law of Identity.
The means by which a proper deduction takes place is logic.
It requires a clear, non-contradictory identification of the conclusion.
(This page mirrored from Importance of Philosophy.com)