Introduction to LogicFaculty: M.Ahamed AmaniTime: 6.45pm to 9.45pm, Tuesday

Course Content: Introduction: Basic Logic Concepts Definitions Types and uses of logic PropositionArgument- Premise and Conclusion Identifying Premise and Conclusion In class Exercise I

Why to study logic ?When we need to do some reliable judgments When the truth is in doubt reason it out

Uses Natural Language may be more complicated Symbolic representation

Definition Logic is the study of the methods and principles used to distinguish correct reasoning from incorrect reasoning.

Proposition

A proposition is something that may be asserted or denied (is or not)Different from Question, Commands and ExclamationTrue or False / Dont know answer

Example: Life in outer space

Proposition and Sentence

Same Meaning Mohamed won the election. The election was won by Mohamed A sentence is always a sentence in a particular languageIn different Context The largest state Texas in the US was once an independent republic

Compound Proposition Proposition within another Proportion The American an Russian were driving swiftly to a junction on the Elbe. The British were at the gates of Hamburg and Bremen and threatening to cut off Germany from occupied Denmark. In Italy Bologna had fallen and Alexanders Allied forces were plunging into the valley of the Po. The Russian, having captured Vienna on April 13, were up the danube.

Compound PropositionThe British were at the gates of Hamburg and Bremen

Is the conjunction of two proposition

The British were at the gates of HamburgThe British were at the gates of Bremen

Compound PropositionThe Conjunctive proposition is itself one component of one large conjunction, that The British were at the gates of Hamburg and Bremen and [ the British] were threatening to cut off Germany from occupied Denmark

Argument An argument is any group of Propositions of which one is claimed to have followed from the others, which are regarded as providing support or grounds for the truth of that one.

Premiss and Conclusion The conclusion of an argument is the proposition that is affirmed on the basis of the other proposition of the argument, and these other propositions, which are affirmed ( or assumed) as providing support or reasons for the accepting the conclusion, are the premisses of that argument.

Simple Argument One premiss and one conclusion Example:No one was present when life appeared on the earth. Therefore any statement about lifes origins should be considered as theory, not fact Premiss: No one was present when life appeared on the earth. Conclusion: Therefore any statement about lifes origins should be considered as theory, not fact

Conclusion stated First:

The food and drug administration should stop all cigarette sales immediately. After all cigarette smoking is the leading preventable cause of death.

Every law is an evil, for every law is an infraction of liberty.

Compound Proposition and ArgumentCompound proposition closely resembles argument : If life evolve on mars during the early period in its history when it had an atmosphere and climate to Earths, then it is likely that life evolved on countless other planets that scientists now believe to exist in our galaxy .

Compound Proposition and ArgumentIt is likely that life evolved on countless other plants that scientist now believe exist in our galaxy, because life very probably evolved on Mars during an early period in its history when it had an atmosphere and climate similar to Earths.Premiss: life very probably evolved on Mars Conclusion: It is likely that life evolved on countless other plants

Exercise1 : Find Argument - Premise and Conclusion A well regulated military force being necessary to the security of a free state, the right of the people to keep and bear arms shall not be violated.Premiss: A well regulated military force being necessary to the security of a free stateConclusion: The right of the people to keep and bear arms shall not be violated.

Find Argument- Premiss and Conclusion

Be careful to judge, for we are sinners allPremiss: We are all sinners

Conclusion:

Be careful to judge

Find Argument- Premiss and Conclusion Because light moves at a finite speed, looking at objects that are millions of miles away is actually looking at light that was emitted many years ago.Premiss:Because light moves at a finite speed

Conclusion: looking at objects that are millions of miles away is actually looking at light that was emitted many years ago.

Find Argument- Premise and ConclusionThe institution of public education thrives on its own failure. The more poorly its charges perform, the more money it asks for ( and gets) from the public and the government. The more money it gets, it can grow itself.

Find Argument- Premiss and ConclusionPremiss: The more poorly its charges perform, the more money it asks for ( and gets) from the public and the government. The more money it gets, it can grow itself.Conclusion: The institution of public education thrives on its own failure.

Find Argument- Premiss and ConclusionUnquestionably, no more important goals exists in medical research today than the development of AIDS vaccine. Last year AIDS, caused by HIV was the infectious disease that killed the most people around the world and the epidemic is not abating.

Find Argument- Premiss and ConclusionPremiss: Last year AIDS, caused by HIV was the infectious disease that killed the most people around the world And the AIDS epidemic is not abating.

Conclusion: Unquestionably, no more important goals exists in medical research today than the development of AIDS vaccine.

Recognizing ArgumentConclusion Indicators:

ThereforeSoAccordinglyIn consequenceHence ThusConsequently Proves thatAs a resultFor this reason

Recognizing ArgumentPremiss- Indicator

Because SinceFor As Follows from As shown byInasmuch as

Types of Logic Deductive reasoning Consists of 3 parts: The major premise, the minor premise and the conclusion. "All men are mortal; Socrates is a man; Therefore Socrates is mortal." The conclusion must be true if the premises are true

Types of LogicInductive Logic

Used in Scientific Project. accumulate all the facts you are using inductive reasoning, that is, using a number of proven facts to draw a general conclusion.

As we have observed for over thousand of years that we conclude all swans are white. What if suddenly a black swan comes out? Would the conclusion that all swans are white be rejected? The answer is no, probably. It would still be true that most of the swans are white. That's why an inductive argument never ends, since it is always open up to the possibility of being unnatural.