Logically Valid Arguments

A formal logic class or textbook should teach us ways to know when an argument has a valid argument form, and that can take a significant amount of time to learn. I encourage everyone to learn formal logic one way or another because it is of central significance to rational argumentation, and it is not something we spontaneously understand instinctively or through personal experience. Perhaps the first philosopher to understand formal logic and the importance of validity was Aristotle, and philosophers would have liked to understand it sooner. It was a great achievement because it can be so difficult to figure out on our own. Even so, we can learn a lot about valid argument form very quickly. I will explain why we need to make sure our deductive arguments are valid, give examples of valid argument forms, and explain how we can improve our arguments.

Why Logic is Important

Recommended reading: What is Logic?

Why is logic education important? The main question here is what the real point of logic education is. The real point of logic is not to teach people how to be logic professors, or to increase test scores, or to impress potential employers. Philosophers and mathematicians were very interested in understanding logic long before it was taught in universities precisely because of how important it is. Why is logic so important? The answer is that logic helps us better understand good arguments—it helps us differentiate between good and bad reasons to believe something. We should want to have well-justified beliefs. We want to know what we should believe. Understanding good argumentation helps us understand when we should believe something, and understanding logic helps us understand good argumentation.

Do Extraordinary Claims Require Extraordinary Evidence?

Do extraordinary claims require extraordinary evidence? Is there a burden of proof against extraordinary claims? Should we literally assume that something extraordinary doesn’t exist until it is proven to exist?

Many people say that those who claim that bigfoot, ghosts, and gods exist are making “extraordinary claims” and we should reject the existence of these things because we don’t have enough evidence for them.

What’s “extraordinary” mean? It refers to claims that conflict with what we think we know about the world. Many claims are extraordinary because they are extreme (likely false) or potentially impossible.

What Are Facts? Do Facts Exist?

Do facts exist? At least one person has claimed that facts do not exist and that thinking they exist would violate Occam’s razor (i.e. multiply entities beyond necessity). However, there is much to be said as to why we have reason to believe that facts exist, such as the reasons to endorse various kinds of realism. I will discuss what facts are, whether they are supposed to refer to something that exists, whether any facts exist, and an objection against their existence. I will argue that all objections to the existence of facts are self-defeating and we have more reason to believe that some facts exist than that no facts exist as a result.

Do Default Positions Exist?

The term “default position” refers to a belief (or lack of belief) that is preferable prior to debate or before any evidence is considered. Many people claim that some belief (or lack thereof) are default positions, so everyone who disagrees with those positions has the burden of proof. What exactly is a default position, and do default positions exist?

What is the Burden of Proof?

One of the most confusing topics regarding argumentation and rationality is what we call the “burden of proof.” What is it? Who has a burden of proof? I will argue that there are two kinds of burden of proof—(1) a principle of debate and (2) a principle of rationality. These two principles are similar but there are important differences. As a principle of debate, the burden of proof determines who needs to prove their assertions. As a principle of rationality, it determines what beliefs are irrational without further evidence in their favor.

Introduction to Argument Mapping Part 2: What is Validity?

What are valid arguments, why are they important, and why is validity often insufficient to have good arguments? I answer these questions and illustrate various points using argument maps.

This is part 2. You might want to see part 1 first. Go here to see part 1.

You can download my Introduction to Argument Mapping as an ebook in PDF form here.

Beliefs Are Innocent Until Proven Guilty Part 2

This is part 2. You should read part 1 first.

I have argued that beliefs are innocent until proven guilty and various objections have been raised to this position and my arguments. I will provide some clarification and respond to various objections here.

Beliefs are Innocent Until Proven Guilty

Many people equate “justified” with “justification”—they think beliefs are justified if and only if we give a good justification for them. A sign of this attitude is found in statements such as, “We should only believe something if we can observe it’s true.” I will explain that not all our beliefs require justifications to be justified because (a) we have justified beliefs that we can’t give justifications for, (b) such an assumption is self-defeating, and (c) such an assumption would lead to an infinite regress or vicious circularity.

No, We Don’t Have To Agree With You!

Do you think everyone has to agree with you about something? Do they have to agree that God exists, Christianity is true, atheism is true, Islam is evil, libertarianism is true, socialism is true, Obama is the antichrist, or Harry Potter is satanist propaganda? Many people seem so confident that they’re right and they know that you need to agree with them. The other person might think that you’re an idiot for not agreeing. This attitude of certainty and confidence often leads to intolerance and insults. Of course, few people are perfect and almost everyone suffers from over-confidence and immodesty at one point or another.

Being Risk-Averse, Hedging Our Bets, and Secularism in Philosophy

We should generally prefer beliefs and theories that are well justified and don’t require ambitious metaphysical or religious assumptions. “Metaphysical” beliefs are beliefs about reality, and “ambitious” beliefs are difficult to justify in a satisfying way that would lead to anything resembling certainty. We attain absolute certainty when we have a belief that couldn’t possibly be wrong.

The Is/Ought Gap: How Do We Get “Ought” from “Is?”

The is/ought gap illustrates the difficulty in understanding what it means to say that we ought to do something, and how we can know what we ought to do. What is the is/ought gap and what’s it all about? I will describe the is/ought gap, discuss its implications in meta-ethics, and discuss various solutions to the is/ought gap.

Philosophical Thought & An Illustration of An Objection

We can learn how to think more like a philosopher by engaging in philosophical debate, reading philosophy, thinking about the nature of philosophical argumentation, and examining the thought process of philosophers. A philosophy professor can be very helpful as a guide to help people engage in philosophical argumentation by helping them verbalize their arguments and avoid fallacious reasoning. Since I am writing about philosophical argumentation, I am not able to help guide your philosophical thoughts as you engage in philosophical debate. However, I can help you peer into the thoughts of someone who engages in philosophical thought. In particular, I will discuss the thinking involved with constructing a philosophical objection.

Writing Philosophical Arguments

Philosophy isn’t just a form of creative writing. It’s an attempt to use good reasoning, and writing good philosophical arguments requires an understanding of good reasoning. Most people have an intuitive grasp of what “good reasoning” is, but this intuitive grasp is often insufficient. Our reasoning can be improved from experience and philosophy education. I will discuss three steps of writing good philosophical arguments:

Four Argument Strategies

Argument strategies are various ways we present our arguments and justifications. Some arguments are simple deductions and generalizations based on our experiences. However, there are a variety of other argument strategies, and a better understanding of them can help us learn to argue more effectively. Argument strategies are usually compatible, and we can often present our justifications using a variety of argument strategies. I will discuss four argument strategies and give examples of these strategies used within the philosophical literature :

Three Forms of Evidence

An argument uses premises to reach a conclusion, but we can’t just accept that every valid argument proves the conclusion to be true. If an argument has a valid form, we need to know that the premises are true before we can know the conclusion is true. We rarely know for certain that the premises of an argument are true. Instead, we do our best at justifying the premises. One way to do this is to provide evidence—reasons we should believe something to be likely true or accurate. Many people equate “evidence” with “observation,” but there could be other reasons to accept beliefs as well. I will discuss three types of evidence:

Five Meta-Ethical Theories

Meta-ethical theories are meant to explain moral psychology, moral reality, and moral reason. Moral psychology considers the actual moral judgments, moral interests, and moral motivation people experience. Moral reality refers to the nature behind true moral statements—what makes our statements true. Moral reason describes our moral knowledge and how we can decide which moral beliefs are best or “most likely true.” Moral realists believe that there are moral facts (moral elements of reality) and they are often optimistic about how well we can understand such facts, but moral anti-realists reject moral realism and don’t think we need moral facts to understand morality. I will briefly discuss five meta-ethical theories, two of which are forms of moral realism and three that are forms of moral anti-realism: Moral naturalism and moral intuitionism are both forms of moral realism; noncognitivism, relativism, and error theory are forms of moral anti-realism. There are many forms of each of these theories, but I will concentrate on one version of each theory.

The Debate Over Moral Realism

The question over what morality refers to has lead to two groups of philosophers. One group describes itself as being “moral realists” and other other as “moral anti-realists.” Moral realists think that there’s more to morality than anti-realists. In particular, the moral realists believes that there’s at least one moral fact. I will describe these two groups then briefly describe why someone might accept or reject moral realism.

Three Kinds of Intuitive Arguments

Our arguments depend on assumptions. We prefer these assumptions to be intuitive and coherent with our other “knowledge” rather than counterintuitive and incompatible with our other “knowledge.” We might not be able to fully explain how we know “1+1=2” but we find it to be an intuitive belief, and we think it’s absurd (and perhaps incoherent) to deny that it’s true. Intuitive arguments are not only very common in philosophy, but it’s possible that all our justifications are grounded in intuition in one way or another.

Arguments for Intuition

Philosophers often discuss what beliefs are intuitive or counterintuitive to support their conclusions. I will argue that we should prefer theories and beliefs that are intuitive or sensitive to our intuitions rather than ones that aren’t.¹ The fact that a theory or belief is intuitive isn’t conclusive proof and a theory or belief being counterintuitive isn’t a conclusive disproof, but it is one important element when evaluating the plausibility of a theory or belief. Intuitive beliefs range from things we know with high degrees of confidence—such as “1+1=2”—to beliefs that are merely plausible enough to take seriously as “possibly true.” When a theory isn’t intuitive, then we call it counterintuitive, absurd, or revisionistic. Revisionism exists in degrees from not at all to totally counterintuitive. I will argue that we should prefer that our theories are intuitive rather than revisionistic for at least the following three reasons: