Our arguments depend on assumptions. We prefer these assumptions to be intuitive and coherent with our other justified beliefs rather than counterintuitive and incompatible with our other justified beliefs. 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.
The following is an example of an intuitive argument:
- Consider the following thought experiment: Jack punches Jill just because Jill has red hair. Intuitively, it seems like Jack did something wrong. Intuitively, we think we know that it’s wrong to punch people with red hair just because they have red hair.
- The best explanation for how we know it’s wrong to punch people with red hair because they have red hair is that we know it’s wrong to harm people without an overriding reason to do so, and having red hair is not an overriding reason to harm someone.
- By reductio ad absurdum (an argument from absurdity), it’s highly intuitive to think that it’s wrong to punch people with red hair because they have red hair considering that it would be absurd to think otherwise. People who think that that punching people because they have red hair aren’t doing anything wrong would seem to have no idea what morality is about. We think we know that it’s wrong to hurt others unless we have an overriding reason to do so, but saying that it’s not wrong to punch people because they have red hair would imply otherwise.
- We have some reason to believe something if it’s the best explanation of highly intuitive beliefs.
- Finally, we may conclude that we have some reason to believe that “it’s wrong to harm people without an overriding reason to do so.”
What exactly an intuitive argument proves depends on the argument. I will discuss three kinds of intuitive arguments with three different purposes: One, to defend that a belief is sufficiently rational. Two, to conclude that a belief is more rational than the alternatives. Three, to conclude that a belief is rationally required.
1. Intuitive Arguments that conclude beliefs to be sufficiently rational
Adequately justified beliefs are sufficiently rational or “rationally permissible.” We can hold these beliefs without being irrational. Rational people can disagree with one another. Perhaps the abortion debate can exemplify the idea of rational disagreement. I can believe that abortion should be legal and you can believe that it should be illegal. As long as we both have good enough reason to support our opinions, both of our beliefs could be rational. This is to be expected considering that we are ignorant and we can’t prove whether abortion should be legal once and for all. Knowing for certain if it should be legal would require many questions to be answered. (Is a fetus a person? Can a person’s right to their own body justify killing something?) Intuitive arguments that attempt to prove that a belief is sufficiently rational, tend to proceed in the following way:
- First, we must prove that we have some reason to accept the belief, or that the belief does not seem to be offensive to reason in general. The belief must be shown to be intuitive (generally through analogy or thought experiment).
- Second, we must prove that we don’t have overriding reason to reject the belief. Objections to the belief are proven not to be serious given our current information.
- Finally, we can then conclude that the belief is intuitive and it’s inoffensive to reason.
The second step is the more important one. If no one can show a belief to be overridingly offensive to reason, then the belief can be generally assumed to be rational. I propose that beliefs are innocent until proven guilty. Being a rational person doesn’t seem to require us to completely prove everything. We have no choice but to have assumptions, and we can’t expect every assumption to be rejected or nothing will be left of our knowledge.
Showing a belief to be overridingly offensive often generally requires that we prove that there’s a better—more intuitive—alternative, but it’s possible that some beliefs are too ambitious or absurd, even when no alternatives are available.
Additionally, some of our permissible beliefs might be more likely false than true. There can be several alternative beliefs and each of them can have a 20% chance of being true, but it could still be rational to believe something that has a 40% chance of being true instead. (Perhaps virtue ethics has a 40% of being true, utilitarianism has a 20% chance of being true, deontology has a 20% chance of being true, and divine command theory has a 20% chance of being true.)
Consider someone who believes that we should improve public education through financial support, even if it requires us to increase income taxes by 1%. Such a belief doesn’t seem irrational. It seems sufficiently intuitive—I certainly think education is important and improving education could be a good idea. Moreover, we know that schools can often be improved through financial support. Other people might object that the money would be better spent elsewhere, but it can be unclear who is right. (Perhaps greater financial support to schools would end up helping people less than using the financial support in some other way.) We could try to show that the money would not be better spent elsewhere to show that it’s rationally permissible to believe that we should improve public education through financial support.
Examples of argument for rational permissibility in the philosophical literature include Thomas Negal’s Possibility of Altruism and Nathan Nobis’s Truth in Ethics and Epistemology. Such arguments didn’t prove that altruism is possible or that moral realism is true, but they do attempt to show these positions to be intuitive and defend them from objections.
2. Intuitive arguments that conclude that a belief is better than the alternatives
Intuitive arguments that attempt to prove that one belief is more intuitive than the alternatives also tend to attempt to prove that the belief itself is intuitive and rationally permissible—that there are no overriding reasons to reject the belief. These arguments are used to attempt to prove the above (that a belief is rationally permissible) in addition to attempting to prove that one belief is better than the alternatives. This is one of the more ambitious forms of argumentation and they are known as supporting arguments because they are used to try to show that one belief is more justified than the alternatives. Philosophers don’t usually think they prove that their beliefs are necessary to be rational nor that alternative beliefs are irrational. Beliefs that are better than the alternatives are the most rational and have the best justification, but the best beliefs are not necessarily mandatory for all rational beings. These arguments almost inevitably make use of arguments from the best explanation. These arguments tend to be argued in the following way:
- First, we must establish that a belief is sufficiently rational. (See above.)
- Second, we must establish that one belief is better than the alternatives. This is often done as an argument from the best explanation. We can compare and contrast each possible relevant belief that we can think of. We can consider objections and evidence for and against each relevant belief.
- Finally, we can then conclude that one belief is the most justified.
An example of an intuitive argument used to conclude that one belief better than the alternatives is Peter Singer’s argument that we have a duty to help others in Rich and Poor (PDF). He asks us to imagine a professor walking to class with no one around except a small child drowning in a shallow pool of water. He suggests that it’s intuitive to think that the professor should assist the child and it’s counterintuitive to say that the professor has no obligation to assist. He thinks that the best explanation for why the professor has an obligation to assist is that there’s a general moral principle that we have a duty to help others when we can do something significant good for others at little to no cost to ourselves.
Arguments used to show that one belief is better than the alternatives are often used to attempt to prove that the alternatives seem counterintuitive or absurd. This is a very strong way to argue because we might then wonder if the alternatives are even rational options. Peter Singer might not think it’s rational to think we don’t have an obligation to help others, although I suspect that he would agree that we can rationally quibble about the precise formulation of the relevant moral principle—how much do we need to help others? Is there a point where helping others becomes supererogatory (above the call of duty)?
Arguments used to show that one belief is better than the alternatives need not mention all alternatives possible, but it ideally should mention alternatives that we know are taken seriously by philosophers. Many of our arguments are part of a greater discussion or dialectic, and we often rely on others to poke holes in our argument. Philosophers often admit that they personally don’t see how any alternatives can make sense and let others have the burden of proof to show otherwise. Consider how Einstein’s theory of physics is assumed to be true because we know of no better alternative to it.
3. Intuitive arguments that conclude that a belief is rationally required
Philosophers agree that many beliefs are irrational. It’s irrational to think that killing people is never wrong, that 1+1=3, that all beliefs are equal, and so on. Irrational beliefs are rarely endorsed by philosophers, but many people do seem to agree to such absurd beliefs. For example, many people say that, “all beliefs are equal.” Philosophers don’t always make it clear when they conclude that a belief is irrational, and arguing that a belief is irrational can be a lot like arguing that a belief is better than the alternatives. Many such arguments look like the following:
- First, we must establish that the belief is rationally permissible.
- Second, we must establish that it is better than the alternatives.
- Third, we must argue that the alternatives to the belief are highly counterintuitive. This can be done by showing that the alternatives are incompatible with other beliefs we know are true with a high degree of certainty using an argument from absurdity (redutio ad absurdum) or by providing very strong objections to all the alternatives.Finally, we can conclude that the belief is rationally required.
For example, consider the argument that it’s irrational to think that “1+1=3” because it’s inconsistent with our mathematical knowledge. The assumption that “1+1=3” will not work out well for us.
Philosophers aren’t always explicit about whether or how their arguments make use of intuition, and they aren’t always explicit about how strong of a conclusion their argument provides—whether they want to say their conclusion is rationally permissible, rationally required, or something in between. Many philosophers will say their argument provides intuitive support or some justification for a conclusion, but that doesn’t necessarily fit the description of any of the kinds of inductive arguments that I discuss here. It’s possible that there’s some reason to believe something, but it might still be irrational to believe it. Arguing that we have some reason to believe something is a very modest way of arguing that avoids being overly ambitious. We don’t want to jump to the conclusion that everyone who disagrees with us is irrational. Nonetheless, it’s rationally required for us to believe that certain statements are false and it is possible to try to debunk irrational beliefs from time to time.