This preview shows pages 1–3. Sign up to view the full content.
UNIT 1
REASON AND ARGUMENT
1.1
WHAT IS MODERN SYMBOLIC LOGIC?
Logic Unit 1:
Introduction
©2011
Niko Scharer
Logic.
The Study & Evaluation of Reasoning & Argument
An argument probably seems
logical
if it look likes the conclusion
must be true, based on what you are told is the case and what you
already know to be true.
This is because logical deductive arguments are
truthpreserving
:
if the premises are true, then the conclusions must be true.
Studying logic can help you recognize which arguments are good
ones, and thus improve your ability to distinguish truths or
probable claims from ones that are poorly supported by the
evidence.
Symbolic.
Use Tidy Symbols instead of Messy Words!
Using symbols instead of words lets you to focus on the logical form of the argument, so you can
evaluate the reasoning of the argument without being distracted by other considerations, e.g. whether
you agree with it, whether it’s interesting or has true premises, etc.
Symbolization also can clear up ambiguities in meaning.
Sometimes sentences, phrases and words can
be interpreted different ways.
Symbolization can force you to be more precise and consider exactly
what is meant.
Modern.
After such people as .
..
•
Aristotle
(384322 BC).
Aristotelian or
syllogistic
logic is
the earliest system intended to classify and evaluate a wide
range of arguments.
•
Chrysippus
(c.280c.205 BC) developed a system of
propositional logic that anticipates modern logic.
•
Gottfried Wilhelm Leibniz
(16461716), perhaps the father
of symbolic logic, developed some of the first logical calculi.
•
Gottlob Frege
(18481925) laid foundations for mathematical
logic, further developed by Alfred North Whitehead (18611947)
and Bertrand Russell
(18721970) in their
Principia Mathematica
.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document1.2
WHAT IS AN ARGUMENT?
In philosophy, logic, essays and many other contexts,
arguments are bits of reasoning which present
justifications for certain statements – a conclusion (a
statement, opinion, thesis, etc.) supported by a
justification or evidence.
An argument is a discourse in which some statements
(the premises) are presented in support of another
statement (the conclusion).
In a valid deductive
argument, the logical structure of that discourse is
such that if the premises are true, then the conclusion
must also be true.
It is
truthpreserving
!
*
Two parts of an Argument
Premises or assumptions:
reasons or justification for the conclusion.
Conclusion:
the statement, thesis or opinion being argued for.
Premises and conclusions are sentences, statements or propositions that can be true or false – they have
truthvalue
.
Arguments are generally composed of statements and usually don’t include questions,
commands and other sentences without truthvalue.
‘Premise’ and ‘conclusion’ are relative terms.
This is the end of the preview. Sign up
to
access the rest of the document.
 Winter '11
 Scharer

Click to edit the document details