Chinese (Mandarin)

Spanish

English

Hindi

Arabic

Portuguese

Bengali

Russian

Japanese

Punjabi

German

Javanese

Malay

Telugu

Vietnamese

Korean

French

Marathi

Tamil

Urdu

Turkish

Italian

Chinese, Yue / Cantonese

Thai

Gujarati

Chinese, Jin

Chinese, Min Nan

Persian, Dari

Persian, Western

Polish

Pashto

Kannada

Chinese, Xiang

Malayalam

Sundanese

Hausa

Odia

Burmese

Chinese, Hakka

Ukrainian

Bihari, Bhojpuri

Tagalog

Yoruba

Bihari, Maithili

Uzbek

Sindhi

Amharic

Fula

Romanian

Oromo

Igbo

Azerbaijani

Chinese, Gan

Dutch

Kurdish, Central

Kurdish, Northern

Kurdish, Southern

Malagasy

Lahnda, Saraiki

Nepali

Sinhalese

Chittagonian

Zhuang

Khmer

Turkmen

Assamese

Madurese

Somali

Marwari

Bihari, Magahi

Haryanvi

Hungarian

Chhattisgarhi

Greek

Chewa

Dakhini

Akan, Twi

Akan, Fante

Kazakh

Chinese, Min Bei

Sylheti

Zulu

Czech

Kinyarwanda

Marwari, Dhundhari

Haitian Creole

Chinese, Min Dong

Ilocano

Quechua

Kirundi

Swedish

Hmong

Shona

Uyghur

Hiligaynon

Mossi

Xhosa

Belarusian

Balochi

Philosophy

<OpenstaxFigure id="fig-00001" src="https://openstax.org/apps/archive/20240226.174525/resources/c9cb37f039d982ed44be778545aa7655ca6061b9" alt="Buddhist monk in red garment bends to speak with other monks in red garments." mediaType="image/jepg" width="1750" height="803" />
<OpenstaxFigureText width="1750">
	<strong>Figure 5.1</strong> Buddhist monks debating at the Sera Monastery in Mysore, India. (credit: modification of “Monks at Sera Monastery 24” by Esther Lee/Flickr, CC BY 2.0)
</OpenstaxFigureText>
<OpenstaxParagraph>
	Within the philosopher’s toolkit, logic is arguably the most powerful tool, and certainly it gets the most use. Logic, the study of reasoning, aims to formalize and describe reasoning processes used to arrive at claims. <OpenstaxTerm>Logic</OpenstaxTerm> is a study of both how we <OpenstaxEm>do</OpenstaxEm> reason and how we <OpenstaxEm>ought</OpenstaxEm> to reason. Logicians categorize and explain different forms of successful reasoning along with mistakes in reasoning, with the goal of understanding what to do right and what to avoid. This chapter seeks to provide you with a general understanding of the discipline of logic.
</OpenstaxParagraph>

5 Logic and Reasoning

1 Introduction to Philosophy

1.1 What Is Philosophy?

1.1.1 Historical Origins of Philosophy

1.1.2 How It All Hangs Together

1.2 How Do Philosophers Arrive at Truth?

1.2.1 Sources of Evidence

1.2.2 Logic

1.2.3 Conceptual Analysis

1.2.4 Trade-offs

1.3 Socrates as a Paradigmatic Historical Philosopher

1.3.1 “The Life Which Is Unexamined Is Not Worth Living”

1.3.2 Human Wisdom Is Worth Little or Nothing

1.3.3 The Importance of Doing No Harm

1.4 An Overview of Contemporary Philosophy

1.4.1 What Can You Do with a Philosophy Major?

1.4.2 An Overview of Your Philosophy Textbook

2 Critical Thinking, Research, Reading, and Writing

2.1 The Brain Is an Inference Machine

2.1.1 The Brain’s Adaptive Ability to Plan Ahead

2.1.2 The Evolutionary Advantage of Shortcuts

2.2 Overcoming Cognitive Biases and Engaging in Critical Reflection

2.2.1 Critical Reflection and Metacognition

2.2.2 Cognitive Biases

2.3 Developing Good Habits of Mind

2.3.1 Strive for Objectivity

2.3.2 Adopt Epistemic Humility

2.4 Gathering Information, Evaluating Sources, and Understanding Evidence

2.4.1 Start with a Strong Foundation

2.4.2 The SIFT Method (Four Moves for Student Fact Checkers)

2.5 Reading Philosophy

2.5.1 Prepare to Read

2.5.2 Engaging with Philosophical Texts

2.5.3 Pre-reading

2.5.4 First Read

2.5.5 Close Read

2.6 Writing Philosophy Papers

2.6.1 Identify Claims

2.6.2 Collect Evidence and Build Your Case

2.6.3 Organize Your Paper

3 The Early History of Philosophy around the World

3.1 Indigenous Philosophy

3.1.1 Challenges in Researching Indigenous Philosophy

3.1.2 Indigenous African Philosophy

3.1.3 Indigenous North American Philosophical Thought

3.1.4 Mesoamerican Philosophy

3.2 Classical Indian Philosophy

3.2.1 The Vedic Tradition

3.2.2 Classical Indian Darshanas

3.3 Classical Chinese Philosophy

3.3.1 Early Chinese Philosophical Thought prior to Confucius

3.3.2 Confucianism

3.3.3 Daoism

3.3.4 Mohism

4 The Emergence of Classical Philosophy

4.1 Historiography and the History of Philosophy

4.1.1 Presentist Approach

4.1.2 Contextualist Approach

4.1.3 Hermeneutic Approach

4.2 Classical Philosophy

4.2.1 Egyptian Origins of Classical Philosophy

4.2.2 Ancient Greek Philosophy

4.2.3 The Presocratics

4.2.4 Socrates and Plato

4.2.5 Aristotle

4.2.6 Epicureans

4.2.7 Roman Philosophy

4.3 Jewish, Christian, and Islamic Philosophy

4.3.1 Defining Jewish, Christian, and Islamic Philosophy

4.3.2 Early Jewish Philosophy

4.3.3 Early Christian Philosophy

4.3.4 Islamic Philosophy

4.3.5 Late Medieval Philosophy in Christian Europe

4.3.6 Jewish Philosophers in the Christian and Islamic Worlds

4.3.7 The Rise of Reason in the Early Modern Era

5.1 Philosophical Methods for Discovering Truth

5.1.1 Dialectics and Philosophical Argumentation

5.1.2 The Use of Reason to Discover Truth

5.1.3 Testing Hypotheses

5.1.4 Laws of Logic

5.1.5 Normativity in Logic

5.2 Logical Statements

5.2.1 Conditionals

5.2.2 Universal Statements

5.3 Arguments

5.3.1 Getting to the Premises

5.3.2 The Difference between Truth and Logic

5.4 Types of Inferences

5.4.1 Deductive Reasoning

5.4.2 Inductive Inferences

5.4.3 Abductive Reasoning

5.5 Informal Fallacies

5.5.1 Fallacies of Relevance

5.5.2 Fallacies of Weak Induction

5.5.3 Fallacies of Unwarranted Assumption

5.5.4 Fallacies of Diversion

6 Metaphysics

6.1 Substance

6.1.1 Fundamentality: The One and the Many

6.1.2 Ontological Perspectives on Substance