Umar Iqbal - Free download as Word Doc (.doc), PDF File (.pdf), Text File (.txt) or read online for free. This document discusses different types of reasoning including deductive, inductive, and abductive reasoning. It defines inference as deriving a conclusion based on existing knowledge. Deductive reasoning uses valid logic to reach necessary conclusions, while inductive reasoning uses probability to reach conclusions that may be incorrect. Abductive reasoning combines deductive and inductive elements to favor the best explanation. The document also discusses forms of flawed, or fallacious, reasoning."> Umar Iqbal">
Logic Umar Iqbal
Logic Umar Iqbal
Logic Umar Iqbal
1. INFERENCE 2
3. VALID INFERENCE 2
4. REASONING 3
5. FORM OF AUGUMENT 3
6. DEDUCTIVE REASONING 3
7. INDUCTIVE REASONING 4
8. ABSTRUCTIVE REASONING 4
9. FALLACIOUS REASONING 5
11. REFRENCES 5
INFERENCE
Inference is the act or process of deriving a conclusion based solely on what one
already knows.
• Human inference.
• Logic studies the laws of valid inference.
The field of half-truths as they relate to the truth of observations, is another area
of concern impacting inference based on observations.
Valid inferences
Inferences are either valid or invalid, but not both. Philosophical logic has
attempted to define the rules of proper inference, i.e. the formal rules that, when
correctly applied to true premises, lead to true conclusions. Aristotle has given
one of the most famous statements of those rules in his Organon.
The reader can check that the premises and conclusion are true. The validity of
the inference may not be true. The validity of the inference depends on the form
of the inference. That is, a valid inference does not depend on the truth of the
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premises and conclusion, but on the formal rules of inference being used. In
traditional logic, the form of the syllogism is:
All A is B
All C is A
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All C is B
Since the syllogism fits this form, then the inference is valid. And if the premises
are true, then the conclusion is necessarily true.
REASONING
Reasoning is the process of looking for reasons on which to base one's beliefs or
actions. In philosophy, the study of reasoning typically focuses on what makes
reasoning good or bad, appropriate or inappropriate. Philosophers do this by
either examining the form or structure of the reasoning within arguments, or by
considering the broader methods used to reach particular goals of reasoning,
such as beliefs or actions. Psychologists, in contrast, tend to study how people
actually reason, and how those methods of reasoning help or hinder people.
Deductive reasoning
The reasoning in this argument is valid, because there is no way in which the
premises, 1 and 2, could be true and the conclusion, 3, be false.
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Validity is a property of the reasoning in the argument, not a property of the
premises in the argument or the argument as a whole. In fact, the truth or falsity
of the premises and the conclusion is irrelevant to the validity of the reasoning in
the argument. The following argument, with a false premise and a false
conclusion, is also valid, (it has the form of reasoning known as modus ponens).
Again, if the premises in this argument were true, the reasoning is such that the
conclusion would also have to be true.
Within the field of formal logic, a variety of different forms of deductive reasoning
have been developed. These involve abstract reasoning using symbols, logical
operators and a set of rules that specify what processes may be followed to
arrive at a conclusion. These forms of reasoning include Aristotelian logic, also
known as syllogistic logic, propositional logic, predicate logic, and modal logic.
Inductive reasoning
1. The sun has risen in the east every morning up until now.
2. So, the sun will also rise in the east tomorrow.
Abductive reasoning
, or argument to the best explanation often involves both inductive and deductive
arguments. However, as the conclusion in an abductive argument does not follow
with certainty from its premises it is best thought of as a form of inductive
reasoning. What separates abduction from the other forms of reasoning is an
attempt to favor one conclusion above others, by attempting to falsify alternative
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explanations or by demonstrating the likelihood of the favored conclusion, given
a set of more or less disputable assumptions.
Fallacious reasoning
Formal Fallacies
Formal fallacies occur when there is a problem with the form, or structure, of the
argument, and, for this reason, always make an argument invalid. Consider, for
example, the following argument:
The reasoning in this argument is bad, because the antecedent (first part) of the
conditional (the 'if..., then...' statement) can be false without the consequent
(second half) of the conditional being true. In this example, the drink could have
been made with boiling milk, or heated in the microwave, and so be hot in spite
of the truth of statement 2. This particular formal fallacy is known as denying the
antecedent.
References
• Jeffrey, Richard. 1991. Formal logic: its scope and limits, (3rd ed.). New
York: McGraw-Hill.
• Vincent F. Hendricks, Thought 2 Talk: A Crash Course in Reflection and
Expression, New York: Automatic Press / VIP, 2005, ISBN 87-991013-7-8
• Scriven, Michael. 1976. Reasoning. New York: McGraw-Hill. ISBN 0-07-
055882-5
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