Logic

Critical Thinking :

3rd Mental Act (Reasoning)

Prof. Isabel De Leon, Ed.D

Reynaldo M. Vianzon Jr.

BSN-3

INTRODUCTION

You assist an evil system most effectively by obeying its orders and decrees. An evil system never deserves such allegiance. Allegiance to it means partaking of the evil. A good person will resist an evil system with his or her whole soul. - - Mahatma GandhiCritical thinking is the disciplined, intellectual process of applying skillful reasoning as a guide to belief or action. In nursing, critical thinking for clinical decision-making is the ability to think in a systematic and logical manner with openness to question and reflect on the reasoning process used to ensure safe nursing practice and quality care (Heaslip). Critical thinking when developed in the practitioner includes adherence to intellectual standards, proficiency in using reasoning, a commitment to develop and maintain intellectual traits of the mind and habits of thought and the competent use of thinking skills and abilities for sound clinical judgments and safe decision-making.

MEANING

"Critical" as used in the expression "critical thinking" connotes the importance or centrality of the thinking to an issue, question or problem of concern. "Critical" in this context does not mean "disapproval" or "negative." There are many positive and useful uses of critical thinking, for example formulating a workable solution to a complex personal problem.

DEFINITIONCritical thinking is the intellectually disciplined process of actively and skillfullyconceptualizing, applying, analyzing, synthesizing, and/or evaluating information gathered from, or generated by, observation, experience, reflection, reasoning, or communication, as a guide to belief and action.

Inference - is the act or process of deriving logical conclusions from premises known or assumed to be true. The conclusion drawn is also called an idiomatic. The laws of valid inference are studied in the field of logic.Inferential thinking is composite of premises or reasons wherein the unknown can be inferred. What is inferred is the conclusion. It begins on what we know called the known. An inference, therefore, is a process of drawing a conclusion from a premise. Judgment is reached indirectly through a third idea or the middle term or through a series of third related ideas.

Methods of Inference

1.Deduction the term deduction is deduced from deduco meaning I lead down. Deduction is an inferential process wherein the mind conclude with certainty from a universal / general principle / knowledge / judgment, to the particular. The premises contain conclusive evidence for the truth of the conclusion.

Example: All tax evaders are corrupt people

But all opportunists are tax evaders

We may infer that, all opportunists are corrupt people.

2. Induction The term induction is deduced from induco meaning I lead into. Induction is an inferential thinking that concludes from individual, or particular to the universal. It claims that its premises furnish only some amount of probability, but not certainty to its conclusion.

Example: My pen, papers, book and erasers are my personal things.

But my personal things are expensive.

Therefore, all my personal things are expensive.

Theoretical Framework

Kinds of Inference

1.Immediate Inference springs directly from a single premise to a conclusion without the mediation of any other premise. A conclusion is drawn from a single premise. The given proposition is called the premise and the proposition deduced or inferred from it is called the conclusion.

2. Mediate Inference the inferential thinking process passes from one proposition to another through a medium. It is called the middle term or another proposition. There is not only a new proposition, but also a new truth, which is drawn by the mind from the first proposition through a medium.

Mediate inference is a mental process. Thus, it exist only in the mind. To represent the argument existing in the mind, it must be expressed by a syllogism.

Syllogism is an external representation of an argument. Etymologically, it is deduced from Greek syn-legein or syn-logos, which, means, to think in a connected manner. It is a series od propositions, viz., first, Major Premise; third, the Conclusion. The conclusion is necessarily derived from the two given premises.

Syllogism - is a kind of logical argument that applies deductive reasoning to arrive at a conclusion based on two or more propositions that are asserted or assumed to be true.

Kinds of Syllogism

1.Categorical Syllogism a deductive argument consisting of three categorical propositions that contain exactly three terms, each of which occurs in exactly two of the propositions. This process of reasoning is grounded on self-evident logical axioms, deduced from the metaphysical principles of identity and contradiction.

2.Hypothetical Syllogism it is a kind wherein at least one proposition is a hypothetical proposition. It does not involve a direct assertion of agreement or disagreement between the subject and the predicate. They express the dependence of the truth or falsity of one statement upon the truth or falsity of another statement.

Varieties of Categorical Syllogism

1. The Enthymeme - is an abbreviated or shortened type of categorical syllogism in that one of its premises or its conclusion is left unexpressed. Enthymemes are of three categories, distinguished on the basis of the missing [art of an argument.

2.The Epichireme - is a type of categorical syllogism whose premise or premise are provided with proofs. The proof is often joined with the premise with a causal connective such as for, because, since, due to, and so on.

3.The Polysyllogism - is a chain of syllogisms which are constructed in a manner that the conclusion of the first syllogism serves as the premise of the next, and so on. The word polysyllogism is derived from the Greek word poly which means many. For the syllogism to be valid each individual syllogism must be valid by observing the rules of simple syllogism. Just one invalid individual syllogism in the series will render the whole chain of syllogism invalid.

4.The Dilemma - is a type of syllogism which combines the conditional and the disjunctive propositions. The major premise consists of two or more additional propositions. The minor premise is a disjunction proposition that their affirms the antecedents or denies the consequents of each of the simple conditional propositions. The dilemma is either constructive or destructive in form.

BibliographyNabor-Nery, Maria Imelda, Fundamentals of Logic, Metro Manila, 2007.http://www.wikipedia.com/Ellen Block, (September 15, 2013). How to deal with Logic. Teen Booklist (Online). HelenSmith@wellington.comStevenson, Rhoda , (January 28, 2014). Humor and immorality. Mind Over Matter (Online). Stevesononline@rehpublishing.com

TABLE OF CONTENTSIntroduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Meaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Inference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Methods of Inference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Theoretical Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Kinds of Inference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Kinds of Syllogism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Varieties of Categorical Syllogism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

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