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Philosophy

<OpenstaxParagraph>
	The sources of beliefs are varied. Perception, reason, hope, faith, and wishful thinking can all result in belief. Yet just because something results in belief, that does not mean that the belief is justified. Beliefs that result from wishful thinking are not justified because wishful thinking does not make a belief more likely to be true. A source of justification is a <OpenstaxEm>reliable</OpenstaxEm> basis for belief. Yet while justification is a reliable source, notice that this does not mean that the belief is true; it just makes it more likely. Justified beliefs can turn out to be false. In order to drive this point home, we will briefly look at four different sources of belief. As you will see, each source is fallible.
</OpenstaxParagraph>
<OpenstaxParagraph>
	One source of belief is <OpenstaxTerm>memory</OpenstaxTerm>. Memory is not always reliable. First of all, that you do not remember something in your past does not mean that it did not happen. Second, when you do remember something, does that guarantee that it happened the way you remember it? Because people can misremember, philosophers distinguish between remembering and seeming to remember. When you actually remember P, then this justifies believing P. When you seem to remember P, this does not justify believing P. The problem is that remembering and seeming to remember often feel the same to the person trying to remember.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Most beliefs are the product of inference. When you use reason to come to belief, the justification you have is inferential; hence, <OpenstaxTerm>inferential justification</OpenstaxTerm> is equivalent to logical justification. But as discussed in the chapter on logic, not all forms of inference can guarantee truth. <OpenstaxTerm>Inductive reasoning</OpenstaxTerm>, which is the most common source of beliefs, is only probable even when done well. Furthermore, people often make mistakes in reasoning. Just because someone reasoned their way to a belief doesn’t mean they reasoned well. But assume for a moment that a person comes to a belief using deductive reasoning, which can guarantee truth, <OpenstaxEm>and</OpenstaxEm> they reason well. Is it still possible that their belief is false? Yes. <OpenstaxTerm>Deductive reasoning</OpenstaxTerm> takes as its input other beliefs to then derive conclusions. In good inductive reasoning, <OpenstaxEm>if</OpenstaxEm> the premises are true (the input beliefs), <OpenstaxEm>then</OpenstaxEm> the conclusion is true. If the input beliefs are false, then even good deductive reasoning cannot guarantee true beliefs.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Another source of belief is <OpenstaxTerm>testimony</OpenstaxTerm>. When you gain beliefs based on the stated beliefs of others, you rely on testimony. Testimony is usually considered something that happens only in a court of law, but in philosophy, the term <OpenstaxEm>testimony</OpenstaxEm> is used much more broadly. Testimony is any utterance, spoken or written, occurring in normal communication conditions. Instances of testimony include news magazines, nonfiction books, personal blogs, professors’ lectures, and opinions volunteered in casual conversation. Often, testimony is a reliable source of information and so can be justified. When you form beliefs based on the testimony of experts, it is justified. But even when justified, those beliefs could be false because experts are vulnerable to all of the weaknesses of justification covered in this section. More will be said about testimony in the section on social epistemology.
</OpenstaxParagraph>
<OpenstaxParagraph>
	Last, <OpenstaxTerm>perception</OpenstaxTerm> can be used as a source of justification. Perception includes the information received from the senses (smell, taste, touch, sight, hearing). People often automatically form beliefs based on perception. However, not all beliefs that follow from perception are guaranteed to be true, as the possibility of knowledge by acquaintance shows. As discussed earlier, <OpenstaxTerm>Russell</OpenstaxTerm> maintained that the only automatically justified beliefs gained from perception are about the existence of sense data (Russell 1948). When looking at the bird outside of my office window, I only have knowledge by acquaintance of <OpenstaxEm>the experience</OpenstaxEm> of seeing the bird on a branch in my visual field. I know that <OpenstaxEm>it seems to me</OpenstaxEm> that there’s a bird. But how do I get from those sense data to the justified belief that there really is bird on the branch? I must rely on another belief about the reliability of my perception—a belief that I can only get by inference, specifically <OpenstaxTerm>induction</OpenstaxTerm>. I reason from past instances where I believe my perception is reliable to the general belief that it is reliable. And of course, induction is fallible. Whenever one moves from knowledge by acquaintance to further beliefs—such as the belief that sense data is caused by actually existing objects—there is room for error.
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<OpenstaxParagraph>
	Not all philosophers agree that all perceptual beliefs are mediated through <OpenstaxTerm>sense data</OpenstaxTerm> (Crane and French 2021). The view called <OpenstaxEm>direct realism</OpenstaxEm> states that people have direct access to objects in the external world via perception. While <OpenstaxTerm>direct realism</OpenstaxTerm> holds that one can directly perceive the external world, it still cannot guarantee that beliefs about it are true, for both hallucinations and illusions are still possible. <a href="#fig-00003">Figure 7.7</a> is an example of an illusion.
</OpenstaxParagraph>
<OpenstaxFigure id="fig-00003" src="https://openstax.org/apps/archive/20240226.174525/resources/3e3292a1c3802fe905789769afed88a462b7bf36" alt="On top, two lines, one with arrows on the end and the other with open V-shaped ends. The line with the V-shaped ends appears to be longer. On the bottom, the same two lines, with dotted lines marking the end points of the lines themselves, demonstrating that they are of equal length." mediaType="image/jpeg" width="600" height="482" />
<OpenstaxFigureText width="600">
	<strong>Figure 7.7</strong> In the Müller-Lyer illusion, the top two lines appear to be different lengths, but the bottom two lines illustrate that the lines are in fact of equal length. (credit: “Müller-Lyer Counter-Illusion” by Subsidiary account/Wikimedia, Public Domain)
</OpenstaxFigureText>
<OpenstaxParagraph>
	If you focus only on the top two lines, it appears as though they are of different lengths. Yet the bottom two lines indicate that this appearance is illusory—the lines are actually of equal length. Illusions function as evidence that perception sometimes misrepresents reality. Even direct realists have to contend with the possibility that beliefs gained through sense perception could be wrong. Hence, sources of beliefs, even when they are usually justified, are nevertheless fallible. The possibility that the subject <OpenstaxEm>could</OpenstaxEm> be wrong is what gives rise to philosophical skepticism—the view that knowledge in some or all domains is impossible.
</OpenstaxParagraph>
<OpenstaxNote>
	<OpenstaxNoteTitle> Think Like a Philosopher </OpenstaxNoteTitle> 
	<OpenstaxParagraph>
		Think critically about the sources of justification explained above. Which of these is more reliable than the others? For each source, identify one instance in which it is reliable and one instance in which it is not.
	</OpenstaxParagraph>
</OpenstaxNote>

7.3.3 The Fallible Nature of Justification

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

5.4.3 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