logic: as tool of philosophy
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Logic: as tool of Philosophy. Science of correct reasoning Nature of man: correct thinking To examine our ability to adapt: in difficult or controversial cases. Organizing ideas/arguments: expressing them with more accuracy drawing legitimate conclusions. FORMAL & MATERIAL LOGIC. - PowerPoint PPT PresentationTRANSCRIPT
Science of correct reasoning1. Nature of man: correct
thinking2. To examine our ability
to adapt: in difficult or
controversial cases.3. Organizing
ideas/arguments: expressing them with
more accuracy drawing legitimate
conclusions.
Logic: as tool of Philosophy
FORMAL LOGIC1. CORRECTNESS RATHER
THAN THE TRUTH Has to do with correctness or
sequence or the following of rules.
2. Not on the material content of the argument.
3. To reason correctly is not necessarily the same as to reason truthfully.
FORMAL & MATERIAL LOGIC
E.g. Formal Logic:
Practice makes perfect
Nobody is perfect
Why practice?
Pag sumama ka sa matalino, tatalino ka rin!
Pag sumama ka sa adik, magiging adik ka rin!
Try mo sumama sa AKIN…
Baka maging AKIN ka rin!
MATERIAL LOGIC1. Concerned with
the truth2. thought-contents
is in correspondence with reality
Connection: mind & real order
E.g. Material Logic
The human soul is endowed with intellect and will;
But, what is endowed with intellect and will is spiritual;
Ergo, the human soul is spiritual.
Potential recruits of Mass Media Industry are students who completed their course in Communication.
I’ve successfully completed my course in Communication last March of 2010.
I am therefore qualified to be a recruit of the Mass Media Industry.
Nature of an argumentArgument is an inferential thinking that is composed of conclusion and premise (assertion/statement) from which the conclusion is inferred.
Inferential: the process of reasoning from a premise to a conclusion; in which the conclusion is drawn from evidential reasoning.
Arguments
E.g. Premise 1: anything that moves is moved by another;
Premise 2: but, the ball moves
Conclusion: therefore, the ball is moved by another.
INFERENTIAL?
PREMISES
CONCLUSION
CLAIMED EVIDENCE
WHAT IS CLAIMED TO FOLLOW FROM THE
EVIDENCE
Valid: (T-T) INFERENTIAL1.The conclusion is true
because of the true premises.
2.It is impossible that the premises of an argument are true and the conclusion false
VALID & INVALID ARGUMENTS
E.g.1. All chickboys have
multiple partners/girlfriends.
2. Ysmael & Iggy Boy have 10 girlfriends each at the same time.
__________________________3. Therefore, Ysmael & Iggy
Boy are both chickboys.
VALID ARGUMENTS
1. All people who are born in the United States are U.S. citizens.
2. Tutoy was born in the United States.
____________________3. Therefore, Tutoy is a U.S. citizen.
VALID ARGUMENTS
1. All mammals have kidneys.
2. Plants do not have kidneys.
____________________3. Therefore, plants are not mammals.
VALID ARGUMENTS
T-FThe premises are true and
the conclusion is false.fallacy of affirming the
consequent.“Inductive: assuming”
“not necessarily… probably!”
(+) If it rains, then the ground gets wet.
(+) But, the ground is wet; (-) Therefore, it rained.
INVALID ARGUMENTS (PRESUMPTUOUS)
1. If Arn-Arn is in Hollywood, then he is in California.
2. Arn-Arn is in California.
______________________3. Therefore, Arn-Arn is in Hollywood.
INVALID ARGUMENTS
1. Horses are not reptiles.
2. Mr. Diego is not a reptile.
_________________3. Therefore, Mr. Diego is a horse.
INVALID ARGUMENTS
“masarap magmahal,
nagmamahal ako, samakatuwid…
masarap ako!”
God is love, but love is blind. Therefore, God is blind!”
F-FThe premises are false (NOT
MATERIAL) and it follows that the conclusion is false(NOT MATERIAL!)
It is valid because: the way in which the premises and conclusion are structured is “FORMALLY CORRECT!”
ALL TREES ARE WOMENBUT, ALL MEN ARE TREESTHEREFORE, ALL WOMEN
ARE MEN
VALID YET ABSURD
One premise: false/trueConclusion: true
(accidental)E.g.
(+) All dogs are animal;
(-) But, all cats are dogs;
(+) Therefore, all cats are animals.
VALID: UNSOUND
VALID ARGUMENTS
PREMISE 1 PREMISE 2 CONCLUSION
VALID/SOUND TRUE (POSITIVE)
TRUE(POSITIVE)
TRUE(POSITIVE)
VALID YET ABSURD
FALSE(NEGATIVE)
FALSE(NEGATIVE)
FALSE(NEGATIVE)
VALID(UNSOUND)
TRUE(POSITIVE)
FALSE(NEGATIVE)
TRUE(POSITIVE)
VALID ARGUMENTS
INVALID ARGUMENTS
PREMISE 1 PREMISE 2 CONCLUSION
INVALID TRUE TRUE FALSE
INVALID ARGUMENTS