1. INDUCTIVE AND
DEDUCTIVE REASONING
Introduction to the Philosophy of the Human Person

2. INTRODUCTION
• Truth lies at the heart of any inquiry. It is a term to
classify any data that has been verified as factual.
• Logic – analysis and appraisal of given arguments

3. SIR FRANCIS BACON
• English Philosopher
• Served as Attorney-General
of England
• While still in college, he
rejected the idea of
Aristotelianism and
Scholasticism
• Pioneer of Empiricism
(Inductive Reasoning)

4. RENE DESCARTES
• French philosopher and
mathematician
• Known for the Cartesian
Plane
• Graduated with a
Baccalaureat and Licence
degree in Law at Université
de Poitiers
• Pioneer of Deductive
Reasoning

5. RENE DESCARTES
• Known for his saying in
French:
“Et remarquant que cette
vérité, je pense, donc je suis ’’
Latin: ‘’Ac proinde haec
cognitio, ego cogito, ergo
sum’’
English: “As I observed as this
truth, I think, therefore, I am”

6. DEFINITION OF REASONING
• It is a capacity of man of consciously thinking about
applying or justifying in a critically and logical way

7. DEFINITION OF PREMISE
• It is a statement that an argument claims will induce or
justify a conclusion.

8. INDUCTIVE REASONING
• Also called as “Socratic Reasoning” because Greek
philosophers Socrates, then Aristotle, popularized the
usage of it
• Making specific arguments from generalized or broad
argument
• General → Specific

9. DEDUCTIVE REASONING
• Making generalized or broad conclusions from specific
arguments or idea
• Specific → General

10. EXAMPLE:
INDUCTIVE REASONING:
Aristotle is a Greek
Greeks are polytheists
Therefore, Aristotle is a polytheist

11. EXAMPLE:
DEDUCTIVE REASONING:
All birds have beaks
An ostrich has a beak
Therefore, an ostrich is a bird

12. MODUS TOLLENS
• “Reasoning of Contrapositive Premises”
• It is a deductive rule that are used in inference or
predictions
• The conclusion usually contradicts the first premise

13. EXAMPLE:
MODUS TOLLENS:
Usually, it is a sunny day if there is low cloud coverage
Right now, there is a high cloud coverage
Therefore, it is not a sunny day

14. ABDUCTIVE REASONING
• Also called as “retroduction”
• Pioneered by Charles Sanders Pierce, an American
philosopher
• It abduces (or take away) a logical assumption,
explanation, inference, conclusion, hypothesis, or best
guess from an observation or set of observations.
• The conclusion may not always be true

15. EXAMPLE:
ABDUCTIVE REASONING:
All mammals don’t lay eggs
Duck-billed Platypus lays eggs
So, duck-billed platypus is not a mammal