Getting started

This page provides a quick introduction to the basic ideas of argument visualization and to using MindMup's argument visualization mode, which you can learn more about under Software. You can find interesting arguments to practice what you learn at the bottom of this page. For more advanced lessons, look under Hints.


Reasons are the basic building blocks of arguments. Reasons aim to raise our confidence in a claim. For example, someone might say, "You shouldn't feel bad that you're going to die because death is inevitable.” Here, the claim that death is inevitable is provided as a reason to believe the conclusion that you shouldn’t feel bad about mortality.

In an argument visualization, reasons are represented using green.

MindMup hint

Attaching a reason to a claim is easy. First, select the claim, and then hit "return"/"enter". Alternately, use the "Add reason" button on the toolbar:

Reasons can contain multiple claims

Notice that if someone said "You shouldn't feel bad that you're going to die because death is inevitable” their argument would be importantly incomplete.

The claim "Death is inevitable" only supports the conclusion "You shouldn't feel bad that you are going to die" when it is supplemented with another claim:

MindMup hint

To add additional claims to a reason (sometimes called "co-premises"), select a claim in the reason and then hit "tab" or use the "Add sibling claim" button on the toolbar:

If some claims support a conclusion only when taken together, place them in a single reason.

In the example above, each claim must be plausible for either one to support for the conclusion.

This is important: If you didn’t believe 2.1, you wouldn’t think that 2.2 supported the conclusion, and if you didn’t believe 2.2, you wouldn’t think that 2.1 supported the conclusion. But if you believed them both, then your confidence in the conclusion would rise. That's why they must be together.

Independent reasons

Argument visualizations also allow us to represent arguments that contain multiple independent reasons for a claim. Here is an example:

MindMup hint

Add independent reasons to support claims just like you added the first: Select the claim you wish to support, then hit Return / Enter. Dragging one claim on top of another will cause the first to become an independent reason for the second.

Note that 2.3 could support the conclusion regardless of the truth of 2.1 and 2.2. In other words, 2.3 is an independent reason to believe the conclusion, and that is why it belongs under its own green bracket.

Test your understanding now:

Which of the two argument visualizations below best represents the following passage?

Being genetically enhanced is only beneficial if it makes you better than other people -- for example, if it makes you taller or better looking than average. But if genetic enhancement technology becomes widely available, everyone will use it, so there’s no point in pursuing genetic enhancement technology.


Objections aim to lower our confidence in a claim. Argument visualizations use red coloring to represent objections:

MindMup hint

To add an objection, select the claim to which you wish to object and then hit "Alt+o" or use the Thumbs-down button on the tool bar. You can also toggle a reason into an objection by hitting "Alt+t" or using the "Toggle" button on the toolbar.

Notice that if you became convinced of 2.3 and 2.4 you would become less confident in the conclusion.

Apart from this one difference, objections work just like reasons.

Unstated assumptions

When people present arguments in writing or speech, they sometimes acknowledge assumptions: "While several of my colleagues in Psychology have argued persuasively against Theory X, in this talk, I assume X is true." It's nice when people are clear about their assumptions, both to themselves and to their audiences. It is also quite rare. In popular media and in articles written for scientists and academics, contestable assumptions are routinely passed over in silence. An important part of improving your ability to read and evaluate argumentative texts is training yourself to detect problematic assumptions in your own and in other people's reasoning.

For example, consider again the first argument presented above: "You shouldn't feel bad that you're going to die because death is inevitable.” What does this argument assume? Plausibly, that you should never feel bad about inevitable things. Perhaps something about this assumption smells fishy to you... It's inevitable (near enough, given the laws of nature) that all sapiens will one day be extinct. Should this recognition make you feel less bad about the possibility of a meteor wiping out humankind forever? I'm inclined to say "no". Having identified an unstated assumption, we are now in a better position to make progress on evaluating the argument.

Unstated assumptions are sometimes also called "implicit claims" to contrast them with claims that an author explicitly makes by writing them down or saying them out loud.

MindMup hint

MindMup allows you to visually mark unstated assumptions (sometimes called "implicit co-premises") by making the border around the claim box dashed. For example, see Claim 2.2:

To mark a claim as implicit, select that claim and then hit Option+t or us the "Toggle" button on the toolbar:

Inferential strength

MindMup doesn't attempt to assess your arguments, but it does allow you to represent your rough sense of how convincing their various inferences are, especially in relation to each other. Consider the arguments given above for the claim that you shouldn’t feel bad that you are going to die. Perhaps you think that Claim 2.3 supports the conclusion more strongly than the reason consisting of Claims 2.1 and 2.2. You can represent this by thickening the connecting line between 2.3 and the conclusion:

MindMup hint

To change the thickness of a connecting line, click it and then select "Stronger" or "Weaker".

Objecting to whole reasons/TRANSITIONS

Sometimes an argument is no good, but not because it contains a false claim. Consider this example:

As the word "law" is used in physics, Claim 2.1 is certainly plausible. But what about 2.2? You might be tempted to respond to this argument: "Sure, if you're talking about human laws—e.g., laws about how fast people may drive on highways—the existence of a law implies the existence of a law giver. (In this case, it implies the existence of someone or something to decide how fast people may drive.) But if we're talking about laws of nature, it's much less clear that laws imply law givers." This suggests an objection to the inference that we can represent like this:

MindMup hint

To object to a whole reason (as opposed to a single claim), select the green bracket and hit Alt+O or use the thumbs-down button on the toolbar.

The red bar is placed under the green bracket to represent that Claim 2.3 objects to the inference rather than the truth of any particular claim.

Here's another way to represent roughly the same thing:

MindMup hint

Notice that the border around Claim 2.3 is dashed to indicate that this claim is assumed by the argument but not stated by the author.

In this visualization, instead of attaching my objection to the inference directly, I've supplied an unstated assumption. This assumption introduces a kind of self-reference into the argument, since Claim 2.3 concerns the meanings of claims in the very argument of which it is a part. This allows us to represent an objection to the inference as an objection to the truth of a specific claim.

Students seem to prefer this approach, but I prefer the earlier one. The visual approach uses a distinct convention to represent the logical difference between (a) objecting to an inference from a set of one or more claims and (b) objecting to some particular claim. This logical distinction deserves to be marked by its own visual convention. (If you're interested to think about why, see Lewis Carroll's 1895 article, "What the Tortoise Said to Achilles".)

What goes in the top box?

The conclusion of an argument is the claim the argument supports (or opposes) overall. In other words, all the other claims in the argument somehow support (or oppose) this conclusion, and the argument does not use the conclusion to directly support (or oppose) any other claim. This does not mean that the conclusion—in the sense relevant here—is always what the author of the passage believes. Sometimes the conclusion is a claim that the author of an argument disagrees with (or doesn't take a side on).

For a concrete example where an author does not necessarily believe the conclusion of the argument, consider this text:

People sometimes argue that medical researchers should not pursue enhancement technology because such technology goes beyond the purpose of medicine. But consider that many medical treatments already accepted as serving the purposes of medicine are not intended to cure illness or reduce discomfort: Plastic surgery and contraceptive medication are just two examples.

The conclusion is that medical researchers should pursue enhancement technology. Does the author believe it? Maybe. But maybe not. You could make an informed guess, but judging from this passage alone, you can’t really be sure. Still, you can be confident that the author doesn't think that Claims 2.3 and 2.4 in this analysis jointly support the conclusion:

The text provides an objection to Claim 2.3, so the above representation works well.

This argument also provides a good example for one last bit of advice to help you get started with visual argument analysis: When you encounter an author objecting to another person's argument, a good strategy is to first figure out the argument to which the author is objecting, and only after you have it figured out, work on attaching the author's objection.

Practice with real arguments

Now that you know the basics, try to analyze these arguments in MindMup AV. If you want to start with an easier challenge, check out the multiple-choice questions below.

Are you a brain in a vat?

Excerpted by Adam Elga, with minor changes, from Michael Huemer's "Epistemology: contemporary readings."

All of your brain’s information about the world comes from electrical impulses that your sense organs and nerves send to your brain. Now, imagine the following scenario. Scientists in a technologically advanced society have figured out how to keep a brain alive, floating in a vat. They have also developed technology for directly stimulating a brain electrically in order to produce a complete set of experiences as of normal life. So why should you believe that this scenario is not actually true, and that you are not, right now, a brain in a vat?

You shouldn’t. That’s because all the evidence you have for or against claims about the external world comes from your sensory experiences. But in the brain-in-a-vat scenario, you would be having the same sort of sensory experiences you are in fact having. So your actual sensory experiences are not evidence against the brain-in-a-vat scenario. So you have no evidence that you are not a brain in a vat. So you shouldn’t believe that you are not a brain in a vat.

Model solution.


Do you think your local butcher will reduce the amount of meat she orders from the slaughterhouse if you become a vegetarian? Of course not! The supply chain for meat just isn’t sensitive to the quantities that a single person consumes. So by becoming a vegetarian, you'll never save a single animal’s life! But by becoming a vegetarian you’ll deprive yourself of the pleasure of eating meat, and you should only do that if the benefits would outweigh the losses. So you should only become a vegetarian if doing so would save some animals’ lives.

Model solution here.

Biological immortality

People often tell me that a good life is supposed to end in old age, but I disagree. I think we have a moral duty to eradicate great evils, so I think we have a moral duty to eradicate aging. Consider an imaginary illness called "HIV/SCHMAIDS." SCHMAIDS is like HIV/AIDS, except at just the point when a person would die from AIDS, they'd spontaneously recover from SCHMAIDS. Now, of course AIDS is way worse than SCHMAIDS. SCHMAIDS, even if it were real, would not be the great evil that AIDS is. So it is really death that is the great evil. But the number of deaths caused by AIDS is tiny compared to the unimaginable carnage of aging: in just two weeks, aging kills around 1.5 million people—more people than AIDS kills in an entire year! Aging is the major cause of death on earth. So aging, too, is a great evil.

Model solution here.

Argument from Illusion

Look around you. What do you see? Perhaps you'll say, “Well, I see the world, of course! The desk; the computer; my partner. What could be clearer?” However, consider that when you look at a straight stick half submerged in water, an optical illusion leads you to see something bent. Now remember, the actual physical stick is straight. The only bent thing for you to see is something mental—a mental image of the stick. And as there isn't any difference in the kind of thing you see in the case of an optical illusion and in normal perception, this demonstrates that in normal visual perception, instead of seeing physical objects, you actually only see your own mental images!

Model solution here.


Created by Adam Elga for Princeton FRS 105, 2013.

Relax! Why are you so worried about that air-raid siren? Look, either there's a bomb out there with your name on it, or not. If there is, nothing you do will stop it from getting you: going to the air-raid shelter won't help, praying won't help, staying out of the open won't help. That's just common sense. And if there's no bomb out there with your name on it, then you might as well relax and enjoy the sunshine out here in the plaza. Everyone knows that what you do can't save your life. Think of it this way. Imagine looking at video tapes of all of the people who died from bombs. None of the measures they took made any difference---even the ones who headed for shelters still got zapped. Now watch the video tapes of all of the people who didn't die from bombs. Nothing they did harmed them---the ones who just sat back and relaxed ended up as alive as the ones who ran around and worried. So stop being an idiot running around looking for the air-raid shelter.

Model solution here.

You can find more exercises in the argument visualization assignments from my course, "A Visual Intro to Philosophy".

Practice with multi-choice-guided visualization problems

For extra practice with the basics of argument visualization, you may wish to attempt some of the exercises embedded below.

Begin by selecting an argument from the list. They are ordered by difficulty from Level 1 - 4, with 1 being the easiest. Begin by copying the text of the argument into a MindMup file and analyzing the argument for yourself using the conventions explained above. Once you're satisfied with your work, go back to the multiple-choice exercise and work through the questions, using them to check your work. Once you have finished the questions in a particular exercise, the suggested solution will be fully revealed.

When your own work disagrees with the solution, make sure you understand where you went wrong: These exercises are only beneficial when you reflect on the feedback.

Note: Due to a Google update, these exercises are temporarily unavailable. Some may be temporarily accessible at

Material on this page is shared under the Creative Commons Attribution-NonCommercial 4.0 International license.