Objectivism In-Brief: Logic
Last modified: December 29, 1995
Logic is the method by which we reach conclusions about reality
based on the evidence of the senses. While most people associate
logic with deductive, mathematical logic, in fact logic is a
broader art. It encompassing both inductive and deductive modes of
reasoning, and it applies to all of our knowledge, not just to
mathematics.
Rand defined logic as ``the art of noncontradictory
identification.'' The two central terms of this definition are
noncontradictory and identification:
is the primary goal of our conceptual
faculty. Our brains are put there to identify---to grasp in
conceptual terms---what is out there in reality.
Noncontradictory refers to the primary rule of
logic: contradictions do not exist. If one arrives at the
conclusion that a ball is both solid gold and solid lead, or that
Socrates is both mortal and immortal, then one has made an error.
All errors in logic ultimately manifest themselves as
contradictory identifications. Although the technical details may
vary among fields of knowledge and among forms of reasoning, the
basic rule of logic is that contradictions do not exist.
Logic begins with the evidence provided by the senses. A process
of thought based on arbitrary premises is not logic. Every
logical conclusion can be traced back to and ultimate grounding in
observation. See knowledge and reason for more on this issue.
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