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Philosophy

<OpenstaxParagraph>
	Abductive reasoning is similar to inductive reasoning in that both forms of inference are probabilistic. However, they differ in the relationship of the premises to the conclusion. In inductive argumentation, the evidence in the premises is used to justify the conclusion. In <OpenstaxTerm>abductive</OpenstaxTerm> reasoning, the conclusion is meant to explain the evidence offered in the premises. In induction the premises explain the conclusion, but in abduction the conclusion explains the premises. 
</OpenstaxParagraph>
<OpenstaxH3>Inference to the Best Explanation</OpenstaxH3>
<OpenstaxParagraph>
	Because abduction reasons from evidence to the most likely explanation for that evidence, it is often called “inference to the best explanation.” We start with a set of data and attempt to come up with some unifying hypothesis that can best explain the existence of those data. Given this structure, the evidence to be explained is usually accepted as true by all parties involved. The focus is not the truth of the evidence, but rather what the evidence means.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Although you may not be aware, you regularly use this form of reasoning. Let us say your car won’t start, and the engine won’t even turn over. Furthermore, you notice that the radio and display lights are not on, even when the key is in and turned to the ON position. Given this evidence, you conclude that the best explanation is that there is a problem with the battery (either it is not connected or is dead). Or perhaps you made pumpkin bread in the morning, but it is not on the counter where you left it when you get home. There are crumbs on the floor, and the bag it was in is also on the floor, torn to shreds. You own a dog who was inside all day. The dog in question is on the couch, head hanging low, ears back, avoiding eye contact. Given the evidence, you conclude that the best explanation for the missing bread is that the dog ate it.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Detectives and forensic investigators use abduction to come up with the best explanation for how a crime was committed and by whom. This form of reasoning is also indispensable to scientists who use observations (evidence) along with accepted hypotheses to create new hypotheses for testing. You may also recognize abduction as a form of reasoning used in medical diagnoses. A doctor considers all your symptoms and any further evidence gathered from preliminarily tests and reasons to the best possible conclusion (a diagnosis) for your illness.
</OpenstaxParagraph>
<OpenstaxH3>Explanatory Virtues</OpenstaxH3>
<OpenstaxParagraph>
	Good abductive inferences share certain features. <OpenstaxTerm>Explanatory virtues</OpenstaxTerm> are aspects of an explanation that generally make it strong. There are many explanatory virtues, but we will focus on four. A good hypothesis should be<OpenstaxEm> explanatory, simple</OpenstaxEm>, and <OpenstaxEm>conservative</OpenstaxEm> and must have <OpenstaxEm>depth</OpenstaxEm>.
</OpenstaxParagraph>
<OpenstaxParagraph>
	To say that a hypothesis must be <OpenstaxEm>explanatory</OpenstaxEm> simply means that it must explain <OpenstaxEm>all</OpenstaxEm> the available evidence. The word “explanatory” for our purposes is being used in a narrower sense than used in everyday language. Take the pumpkin bread example: a person might reason that perhaps their roommate ate the loaf of pumpkin bread. However, such an explanation would not explain why the crumbs and bag were on the floor, nor the guilty posture of the dog. People do not normally eat an entire loaf of pumpkin bread, and if they do, they don’t eviscerate the bag while doing so, and even if they did, they’d probably hide the evidence. Thus, the explanation that your roommate ate the bread isn’t as explanatory as the one that pinpoints your dog as the culprit.
</OpenstaxParagraph>
<OpenstaxParagraph>
	But what if you reason that a different dog got into the house and ate the bread, then got out again, and your dog looks guilty because he did nothing to stop the intruder? This explanation seems to explain the missing bread, but it is not as good as the simpler explanation that your dog is the perpetrator. A good explanation is often <OpenstaxEm>simple</OpenstaxEm>. You may have heard of <OpenstaxEm>Occam’s razor</OpenstaxEm>, formulated by William of Ockham (1287–1347), which says that the simplest explanation is the best explanation. Ockham said that “entities should not be multiplied beyond necessity” (Spade &amp; Panaccio 2019). By “entities,” Ockham meant concepts or mechanisms or moving parts.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Examples of explanations that lack simplicity abound. For example, conspiracy theories present the very opposite of simplicity since such explanations are by their very nature complex. Conspiracy theories <OpenstaxEm>must</OpenstaxEm> posit plots, underhanded dealings, cover-ups (to explain the existence of alternative evidence), and maniacal people to explain phenomena and to further explain away the simpler explanation for those phenomena. Conspiracy theories are never simple, but that is not the only reason they are suspect. Conspiracy theories also generally lack the virtues of being <OpenstaxEm>conservative</OpenstaxEm> and having <OpenstaxEm>depth</OpenstaxEm>.
</OpenstaxParagraph>
<OpenstaxParagraph>
	A <OpenstaxTerm><OpenstaxEm>conservative</OpenstaxEm> explanation</OpenstaxTerm> maintains or <OpenstaxEm>conserves</OpenstaxEm> much of what we already believe. Conservativeness in science is when a theory or hypothesis fits with other established scientific theories and explanations. For example, a theory that accounts for some physical phenomenon but also does not violate Newton’s first law of motion is an example of a conservative theory. On the other hand, consider the conspiracy theory that we never landed on the moon. Someone might posit that the televised Apollo 11 space landing was filmed in a secret studio somewhere. But the reality of the first televised moon landing is not the only belief we must get rid of to maintain the theory. Five more manned moon landings occurred. Furthermore, the reality of the moon landings fits into beliefs about technological advancement over the next five decades. Many of the technologies developed were later adopted by the military and private sector (NASA, n.d.). Moreover, the Apollo missions are a key factor in understanding the space race of the Cold War era. Accepting the conspiracy theory requires rejecting a wide range of beliefs, and so the theory is not conservative.
</OpenstaxParagraph>
<OpenstaxParagraph>
	A conspiracy theorist may offer alternative explanations to account for the tension between their explanation and established beliefs. However, for each explanation the conspiracist offers, more questions are raised. And a good explanation should not raise more questions than it answers. This characteristic is the virtue of <OpenstaxEm>depth</OpenstaxEm>. A deep explanation avoids <OpenstaxEm>unexplained explainers,</OpenstaxEm> or an explanation that itself is in need of explanation. For example, the theorist might claim that John Glenn and the other astronauts were brainwashed to explain the astronauts’ firsthand accounts. But this claim raises a question about how brainwashing works. Furthermore, what about the accounts of the thousands of other personnel who worked on the project? Were they all brainwashed? And if so, how? The conspiracy theorist’s explanation raises more questions than it answers.
</OpenstaxParagraph>
<OpenstaxH3>Extraordinary Claims Require Extraordinary Evidence</OpenstaxH3>
<OpenstaxParagraph>
	Is it possible that our established beliefs (or scientific theories) could be wrong? Why give precedence to an explanation because it upholds our beliefs? Scientific thought would never have advanced if we deferred to conservative explanations all the time. In fact, the explanatory virtues are not laws but rules of thumb, none of which are supreme or necessary. Sometimes the correct explanation is more complicated, and sometimes the correct explanation will require that we give up long-held beliefs. Novel and revolutionary explanations can be strong if they have evidence to back them up. In the sciences, this approach is expressed in the following principle: <OpenstaxTerm><OpenstaxEm>Extraordinary claims</OpenstaxEm></OpenstaxTerm> <OpenstaxEm>will require extraordinary evidence.</OpenstaxEm> In other words, a novel claim that disrupts accepted knowledge will need more evidence to make it credible than a claim that already aligns with accepted knowledge.
</OpenstaxParagraph>
<OpenstaxParagraph>
	<a href="#table-00001">Table 5.2</a> summarizes the three types of inferences just discussed.
</OpenstaxParagraph>
<OpenstaxTable id="table-00001">
	<OpenstaxThead>
		 
		<OpenstaxTr>
			 
			<OpenstaxTh>
				Type of inference
			</OpenstaxTh> 
			<OpenstaxTh>
				Description
			</OpenstaxTh> 
			<OpenstaxTh colspan="2">
				Considerations
			</OpenstaxTh> 
		</OpenstaxTr> 
	</OpenstaxThead>
	<OpenstaxTbody>
		 
		<OpenstaxTr>
			 
			<OpenstaxTd>
				Deductive
			</OpenstaxTd> 
			<OpenstaxTd>
				Focuses on the structure of arguments
			</OpenstaxTd> 
			<OpenstaxTd>
				Provides valid inferences when its structure guarantees the truth of its conclusion
			</OpenstaxTd> 
			<OpenstaxTd>
				Provides invalid inferences when, even if the premises are true, the conclusion may be false
			</OpenstaxTd> 
		</OpenstaxTr> 
		<OpenstaxTr>
			 
			<OpenstaxTd>
				Inductive
			</OpenstaxTd> 
			<OpenstaxTd>
				Uses general beliefs about the world to create beliefs about specific experiences or to make predictions about future experiences
			</OpenstaxTd> 
			<OpenstaxTd>
				Strong if the conclusion is probably true, assuming that the evidence is true
			</OpenstaxTd> 
			<OpenstaxTd>
				Weak if the conclusion is probably not true, even if the evidence offered is true
			</OpenstaxTd> 
		</OpenstaxTr> 
		<OpenstaxTr>
			 
			<OpenstaxTd>
				Abductive
			</OpenstaxTd> 
			<OpenstaxTd>
				An explanation is offered to justify and explain evidence
			</OpenstaxTd> 
			<OpenstaxTd>
				Strong if it is explanatory, simple, conservative, and has depth
			</OpenstaxTd> 
			<OpenstaxTd>
				Extraordinary claims require extraordinary evidence
			</OpenstaxTd> 
		</OpenstaxTr> 
	</OpenstaxTbody>
</OpenstaxTable>
<OpenstaxTableTitle>
	<strong>Table 5.2</strong>  - Three Types of Inferences
</OpenstaxTableTitle>

5.4.3 Abductive 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 Logic and Reasoning

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

5.5 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

Question	Answer
having to do with abduction/abductive reasoning. Abduction is probabilistic form of inference in which an explanation is offered to justify and explain evidence.	Abductive
aspects of an explanation that generally make it strong; four such virtues are that a good hypothesis should be explanatory, simple, and conservative, and have depth.	Explanatory virtues