PHIL 201STUDY GUIDE: LESSON 4A Little LogicLesson OverviewLogic is the primary tool or methodology in studying philosophy. Philosophy is about analyzing and constructing arguments and a good understanding of the basics of logical reasoning is essential in performing that task. The next 3 lessons will focus on logic and analyzing arguments.In this lesson, you will first be introduced to the laws of logic. These are the first principles for all reasoning. We will then discuss the specialized terminology we use in logic. Finally, we will examine 2 major kinds of logical reasoning: deductive and inductive. We will consider different forms of arguments under each and discuss how to evaluate these arguments. Take note that a large part of this lesson is about learning the terminology for logic.TasksView the Presentation: “Deductive and Inductive Arguments” as it is a good summary of some of the reading in this module/week.Read and take notes from Prelude to Philosophy, Chapter 5: “A Little Logic.” As you read, makesure you understand the following points and questions:- Why are the laws of logic foundational?o They make discourse possible. If they are not recognized as true, the nothing we claim makes any sense.- List and explain the 3 laws of logic.o The Law of Noncontradiction: something cannot both be and not be at the same time and in the same respect .o The Law of Excluded Middle: something either is.o The Law of Identity: something is what it is. “P = P”- Know the symbolic expression of the law of non-contradiction and how it clears up confusions.o (P • P) “It is not the case that there can be both P and non-P.”⁓- Explain the common confusion concerning God and contradictions.o That God is omnipotent and therefore can do anything, including contradictions, also using quote Matthew 19:26.- Know the symbolic expression of the Law of Excluded Middle. Why is it called the Law of Excluded Middle?o P v P “Either P or non-P”⁓o It is calle this because it exludes the possibility of something in the middle of existence and nonexistence; the thing either exists or it doesn’t. NO THIRD WHAT.- Know the why the laws of logic are self-evident.o It claims that whatever a particular thing is, it is that particular thing. It takes into account that different terms might refer to the same thing (“Clark Jent” and “Superman” are 2 different terms, but refer to the same person.)Page 1 of 5PHIL 201- Know the three parts of an argument.o Propositions, a conclusion, and interference- Distinguish the language of evaluating arguments (deductive and inductive) from how weevaluate propositions.o Deductive: are evaluated as either valid or invalid.o Inductive: are either strong or weak.- Explain the relationship between truth value of the propositions with the validity/strength of the argument.o The validity or strength of an argument and the truth value of the propositions are two distinct and separate aspects of an argument. The truth value of the propsitions in an argument has nothing to do with its vailidity or strength, and vailidty or strength has nothing to do with true value.- Know the point about agreeing with the conclusion of an argument and it being a good argument.o “Do not assume that because you agree with the conclusion of an argument it must be a good argument.”- Know the kind of conclusion arrived at by a valid deductive argument.o In a valid deductive argument, the premises guarantee the conclusion with logical certainty.- Note the difference in terminology between the laws of logic and the rules of valid inference.o A syllogism is a logical argument that consists of two premises and a conclusion that is structured according to certain rules of valid inference that govern the particular type of syllogism being employed. If the syllogism keeps the rules, it is valid. If it breaks any of them, it is invalid.- Explain the categorical syllogism (you did not need to memorize the chart nor the 6 rules of valid inference).Name Type Model ExampleA Universal – Affirmative All S are P All students are kind.E Universal – Negative No S are P No students are kind.I Particular – Affirmative Some S are P Some students are kind.O Particular – Negative Some S are not P Some students are not kind.A categorical syllogism features three categorical propositions: amajorpremise, aminor premiseand theconclusion. It also contains three termsand only three terms, each term being used twice.Here is an example:AllMareP. (major premise)SomeSareM.(minor premise)SomeSareP.(conclusion)- Explain the disjunctive syllogism and know the fallacy.o One must deny one of the alternatives in the second premise and affirm the other alternative in the conclusion.Page 2 of 5PHIL 201o This rule is not to deny that there are exclusive disjunctive propositions, such as the law of excluded middle. Sometimes there are only two possibilities where the case must be one or the other and both cannot be true. For example, a person mustbe dead or alive. She cannot be both and must be one or the other. - Explain what a hypothetical proposition is doing and what it is not doing.o If A, then B. If B, then C. Therefore, if A, then C.o- Explain the hypothetical syllogism and know the two fallacies.o Is built around a hypothetical statement which takes the form: “IF…THEN.” Hypothetical syllogisms are not entirely hypothetical, but one of its premises is. 3 Hypothetical statements would not lead to any conclusions. Denying the Antecedent Affirming the Consequent- Contrast induction with deduction.o In a valid deductive argument, the conclusion follows necessarily from the premises. So, if the premises are assumed to be true, the conclusion necessarily must be true. It is impossible for the conclusion to be false. This never the case foran inductive argument. In a strong inductive argument, the conclusion only probably follows from the premises. That is, assuming the premises are true, athe conclusion is only probably.- How are inductive arguments evaluated in comparison to deductive arguments and what makes an argument stronger or weaker?o Deductive reasoning has only two possible evaluations: the argument is either valid or invalid. However, in evailating inductive arguments a number of options are possible.o A strong inductive argument is one where, assuming the premises are true, the