Philosophy,logic and its kind,inductive and deductive reasoning ppt
Miss Iram Saba
HISTORY OF LOGIC
The term "logic" came from the Greek word logos, which is sometimes
translated as "sentence", "discourse", "reason", "rule", and "ratio".
Logic was studied in several ancient civilizations, including India, China,
Persia and Greece.
In the West, logic was established as a formal discipline by Aristotle,
who gave it a fundamental place in philosophy.
In the East, logic was developed by Buddhists.
DEFINITION OF LOGIC
Logic is the systematic process of valid reasoning through inference —
conclusions from information that is known to be true. It is the area of
philosophy that is concerned with the laws of valid reasoning.
TYPES OF LOGIC
Formal Logic: It is mainly concerned with formal systems of logic. These
specially constructed systems for carrying out proofs, where the languages
rules of reasoning are precisely and carefully defined.
Reason for studying Formal Logic:
Its helps us to identify patterns of good reasoning and patterns of bad
reasoning, so we know which to follow and which to avoid.
help improve critical thinking.
Its also used by linguists to study natural languages.
Computer scientists also employ formal systems of logic in research
relating to Artificial Intelligence.
TYPES OF LOGIC
Informal Logic: The term "informal logic" is often used to mean the same
as critical thinking. Sometimes it is used to refer to the study of reasoning
fallacies in the context of everyday life.
Symbolic Logic: Symbolic logic is the method of representing logical
expressions through the use of symbols and variables, rather than in
IMPORTANCE OF LOGIC
A study of logic can help a person better construct their own arguments
Critique the arguments of others. It isn't uncommon for many popular
arguments to be filled with errors and fallacies because so many people are
simply unaware of how arguments are correctly formulated.
The two main methods of reasoning are called deduction and induction.
Deduction: It works from the general to the more specific. In deduction,
the conclusion is logically follows from the premises; it is a necessary
conclusion and is true.
Examples of Deductive Logic:
All squares are rectangles. All rectangles have four sides. Logic,
therefore, tells you that all squares have four sides.
It is dangerous to drive when it is snowing. It is snowing now. Logic tells
you that it would be dangerous to drive right now.
When it rains the trees get wet. The trees are wet this morning, so it
rained last night.
Induction: Where induction moves from the specific to the general. In
induction, the conclusion "probably" follows the premises and is not
Examples of Inductive Logic:
Every three year old you see at the park every afternoon spends most of
their time crying and screaming. Your conclusion is that all three year
olds spend their afternoon screaming.
Every house that burned down on the block was caused by faulty wiring.
You conclusion is that all homes on the block have faulty wiring.
Inductive reasoning works the opposite way, moving from specific
to broader generalizations and theories. This is sometimes called a “bottom
up” approach. The researcher begins with specific observations and
begins to then detect patterns and regularities, formulate some tentative
hypotheses to explore, and finally ends up developing some general
conclusions or theories.
Example: An example of inductive reasoning can be seen in this set of
statements: Today, I left for work at eight o’clock and I arrived on time.
Therefore, every day that I leave the house at eight o’clock, I will arrive to
Deductive reasoning happens when a researcher works from the more
information to the more specific. Sometimes this is called the “top-down”
approach because the researcher starts at the top with a very broad
of information and they work their way down to a specific conclusion.
Example: Every day, I leave for work in my car at eight o’clock. Every day,
the drive to work takes 45 minutes I arrive to work on time. Therefore, if I
leave for work at eight o’clock today, I will be on time.
As these examples show, you can use logic to solve problems and to draw
conclusions. Sometimes those conclusions are correct conclusions and
sometimes they are inaccurate. When you use deductive reasoning, you
at correct logical arguments while inductive reasoning may or may not
you with a correct outcome.