The term non-sequitur

As Wikipedia notes,i the term is used in everyday speech to deny a conditional (if-then statement), and it is also used in logic to mean an invalid argument. This together with the fact that in normal language people do not write the complete arguments when they argue, makes it very easy to confuse things.

Suppose that someone says “Since that global warming is undesirable, we ought to not burn more coal.” Another person then responds to that with “Non-sequitur“. What did the second person criticize? The argument structure or validity? That structure is hidden and we have to guess at what it is. (Se Note 1.) The conditional? Maybe.

We should therefore at least not use the term ‘non-sequitur’ without also clarifying what the problem is. But we ought not to use the term at all since there are better alternatives. If one means that the argument is invalid, then say “The argument is invalid”. If one means that a conditional is false, then say “The conditional is false.”. This recommendation is for discussions of a certain quality only. Chances are that if you argue with a random member of the mob, then that person will not know what it means to say that an argument is invalid or what a conditional is.

There are also similar phrases such as ‘That doesn’t follow’. Non-sequitur is latin for ‘it does not follow’.

Note 1

The principle of charity applies in that case. We don’t know which argument structure the person had in mind when making the argument. If it is member of the mob, then he or she probably doesn’t know either which structure it has. But if we should follow the aforementioned principle, then we ought to make an interpretation of the argument in question that is valid. This is sometimes a task in itself.

Discussions on the internet


I have a couple of thoughts related to discussing things on the internet that I want to share. These thoughts are about active networking, being effective and having the goal in mind, avoiding unproductive people etc.

Realization of why one is discussing

First one ought to make it clear to oneself why one is discussing on the internet; What is one trying to obtain? Some are undoubtedly there to “fight” battles for a variety of reasons. Perhaps because they deem it fun or entertaining or to get self-confidence by “slaying noobs”.

But I’ll admit that this is not my primary goal. By primary goal I mean that it is mostly not what I aim to get out of a discussion. I aim to improve my philosophical understanding and have a few laughs on my way there. I suppose that this is many people’s desire. At least, the philosopher type people I like to identify with.

However, this outcome, that is, improving one’s philosophical understanding, does not come easy. One has to learn how to communicate in a useful way. By useful I mean a way that is optimal for whatever one is doing. I’m assuming here that one is trying to improve one’s philosophical understanding in a broad sense, and thus I’ll focus on reaching exactly that. In some cases this can be substituted for whatever subject it is that one is interested in. Some of my points may also hold for other subjects.

Is one in the right place? – Part 1

Discussion on the internet usually takes place in forums. Forums are designed to be a good place to discuss. However, some people like to discuss in other places like comment sections, instant messengers etc. I recommend not using a suboptimal medium to discuss in, such as an instant messenger. The reason why instant messengers are not a good communication tool for discussion is that they emphasize the quickness of the response which is irrelevant for a good argument. Good choices are forums and emails or private messages sent via private message systems. Such systems are usually in place at forums.

The reason that they are good choices is that they allow for easy quoting of others’ words, and they give an overview.

There are also differences between them. Forums are more often used as fight places. When talking “public” people are probably more reluctant to admit that they are wrong in order to avoid losing pride. This is a human trait that ought to be avoided if possible. It can be done by remembering why one is discussimg: To get a better philosophical understanding, not to have a renown internet personality. One can reduce the personality issue by being anonymous, so that the only “person” that loses pride is the name on the screen. If it gets really bad, one can always create a new user and start out anew. Forums are better if one’s goal is to get opinions from many people; Such as getting general comments on some important argument. In-deep discussions can hereafter take place either in the public forum or in private communications.

The advantage of email is that the personality issue is less there; People are less reluctant to admit mistakes when there is only one person that will know. Also keep in mind that e-mails can be used anonymously too. A disadvantage of e-mail or private messages is that the information is not publicly viewable. This means that unless one afterward shares the emails with a third part, others will not benefit from reading the discussion.

Is one in the right place? – Part 2

Though, there are other things than the medium to take into account. There is also the community. This obviously relates to the question of whom one is going to discuss with. One would not want to discuss with people who’s goal is to “fight”, as mentioned earlier. One would want to discuss with people who also share the desire of improving one’s philosophical understanding. Such people can be very hard to come by. One should try to get a good look at the forum discussions to get an idea about the general level of the discussion. Afterward one can answer the questions: Is it worth participating here?; What will I probably get out of it if I participate?

Participation, however, might not be needed. There is no reason to just repeat something that was already stated clearly. One can learn a lot by just reading. Think of it like reading a book where one has the opportunity to write something and change the story. This does not imply that one ought to write something. It might be a good idea just to let it run.

Avoiding unproductive people

This is basic networking. Don’t waste your time with people who will not help you reach your goal(s). This could be, but is not limited to, people who like to “fight”, or people who are too stupid to learn you anything. Stay around productive people. Avoid responding to people who are unproductive. If you wish, you can reply that you find them unproductive and thus do not want to engage in discussion with them. In this way it will seem as if you don’t have any counter-arguments, though this shouldn’t matter much to one as it is only a personality issue which I mentioned earlier.

The idea of working beliefs

Suppose you want to examine some proposition. How would you go on doing that? One could contemplate it oneself, and then decide what to believe. The problem is that often when one studies something only oneself, then one will probably miss some things, at least one will miss things that are obvious to other people. Some of these things might be critical to the examination of a belief. If one is really interested in truth, then one wants to see the best arguments for all sides. A good way to get familiar with such arguments is to discuss the issue with people who are intelligent and fairly well-read. This method is especially useful if one cannot find a good article or book published on the issue, or that this is too expensive etc.

Discussions on the internet are typically separated into different threads. This gives a very good opportunity to test beliefs. One can start a new thread and then pretend to believe something, and give the best arguments one knows for that specific belief. Others will then, hopefully. supply counter-arguments. After some discussion one can assess the total available evidence and then form more well-researched belief than if one had only examined it oneself.

However, one should avoid testing too stupid beliefs for that might get reasonable people to think that one is a troll or just really stupid, and thus to not respond to posts that one makes in other threads too.

Another advantage with working beliefs is that one avoids the embarrassment of having been proved wrong. One should simply state in the beginning of the thread that one is defending a working belief to see how it goes.


We’re all fallible creatures. When one doesn’t know what one is talking about, one should admit it. Think about how many times you have been wrong in the past. This is good inductive evidence that you will be wrong in the future; What possible reason do you have for thinking that you’ve got it exactly right this time? (I.e. since the last time you changed your beliefs.) It’s a good idea to keep one’s ignorance in mind when discussing. People generally don’t like people who act or write like they know everything already. After all, if you already know everything there is to know about a subject, why are you on the discussion board? To preach your position?

Of course, one ought not to claim too much ignorance either. People who claim to be ignorant about things they clearly know about are lying, and thus untrustworthy. Realize that you’re not superman, you’re not right about everything you believe, but if you set your mind to it, you will improve your understanding and get rid of many of the wrong beliefs that you hold.

Synthesis, cooperation

When discussing some completely new problem, i.e. one that was not hitherto known to the participants in the thread, it is probably a good idea to try to invent a theory together that can solve the problem. Other participants are not your enemies, for all you know, you might end up agreeing with them. Try to cooperate with other people to figure out the situation. There is no reason to try to stand out from the crowd. The majority view is not always correct, but it is not always wrong either.

Writing in a friendly language, mind-reading, psychological explanations

Writing in a friendly language may get you some new friends, reduce hostilities from other participants, and help keep focus on the issue in the thread instead of on personal issues. Friends you earn this way may be helpful in reaching your goals too. For instance, they could offer to proof-read and comment articles you write before you publish them.

Try to avoid mind-reading the other participants. If you need to know their opinion about something, ask them. Wrongly assuming their position is unproductive and happens a lot on forums. It will just inflame things with accusations of “straw man!” flying around.

Try to avoid writing psychological explanations of why people believe what they do. Such explanations often beg the question and are thus unproductive. They also, sometimes, insult the other participants. If you find it very important to tell a particular person why you think they believe what they do, then write it in very friendly language and sent it as a private message or email. Such explanations also derail the thread, moving the attention from the issue to other irrelevancies.

Principle of charity, language

As mentioned earlier, after a long discussion it may happen that you come to agreement with the person or persons that you’ve been discussing with. Many times people get stuck in their language choice or use. One ought to realize that common language is broad and can be used in ways you don’t normally use it. One ought to attempt to understand what then other person believes instead of just (almost mechanically) replying to what they write. Sometimes people choose a wrong word to express their belief. Ask yourself what your goal is: Is it to show that some particular belief is wrong, or to find out what the other person believes and to have a productive discussion? Think about it, there are billions of wrong beliefs. One cannot demolish all of them. There is only a point in demolishing a belief when one knows that there are people who believe it.

There is a principle related to this, the principle of charity: When one reads a text and have multiples theories or interpretations of what the author means, one should always assume that the author means the most probably interpretation of the text. If multiple theories are plausible, one should either address all of them or ask the author for clarification.

Belief, disbelief; agreement, disagreement

There is often some confusion surrounding the terms: belief, disbelief, agreement and disagreement when used in a philosophical context. We need to keep in mind that normal dictionary definitions are often not precise enough to be used in a philosophical context where precision and clarity are essential. (For analytic philosophy.) In this article I will explain the terms ‘belief’ and ‘disbelief’, and ‘agreement’ and ‘disagreement’. Then I will suggest a new way to define the terms in the name of clarity.

Belief and disbelief

I’m not going into some advanced theory of how humans believe things. I’m merely going to the contrast between believing something and disbelieving something. The confusion lies not with the word ‘belief’ but with the word ‘disbelief’. Some take ‘disbelief’ to be a mere lack of belief in something. Others take ‘disbelief’ to be a belief in the negation of something. It is this latter meaning that is usually meant in philosophical context. Going by the normal meaning of ‘belief’ and the second meaning of ‘disbelief’ we should then be able to see that this is a false dichotomy; One does not either believe something or disbelieve in something. There is a third option, that is, that one has no belief at all on the matter.1 Here’s a table that shows trichotomy along with a symbolic logic representation of the options:

Options Formalization
I believe something. B(p)
I don’t have any opinion about something. ¬B(p)∧¬B(¬p)
I disbelieve in something. B(¬p)

Note: Replace ‘something’ in the table with some particular proposition. Philosophers usually just write p which is what I have done in the formalization to the right.

The confusion is often between row number two and row number three. Especially when the ambiguous phrase “I don’t believe that something” is used. Taken literally this phrase means the first part of the second row2 but people usually mean the third row when they say it.

I suggest that, for the sake of clarity, that one ought to use “I believe something” to mean the first row, “I have no opinion about something” to mean the second row, and “I disbelieve in something” to mean the third row. To mean a lack of belief in something I suggest using the phrase “I have no belief that something”. Avoid using the phrase “I don’t believe that something” because it is ambiguous.

Agreement and disagreement

Having understood the above we can move on to the second part of this article. I suggest that we define agreement and disagreement in an analogous way to the above defined words. This means that to be in agreement about something with someone is to believe the something that the other person believes. To disagree with someone about something is to believe the negation of what the other person believes. Note that the common usage of ‘disagree’ is to merely not believe the something that the other person believes. I suggest that if one wants to say that one does not believe the something it is that the other person believes, then one ought to say “I don’t agree”. If one accepts this redefinition in the context of philosophy, then one should see that the dichotomy between agreeing and disagreeing is false. It is possible to not hold an opinion at all about something.

1I mean ‘the matter’ in a strict sense. Here’s an example. Suppose the matter is ‘one ought to vote for the republican party’. Then the matter is only that. Beliefs about whether one ought to vote or note, or to vote for the democratic party are not relevant.

2That one has no belief in something. [¬B(p)]

Two kinds of certainty

A quick explanation of two types of certainty that people tend to confuse.

The first is the one we typically mean in natural language. It’s called psychological certainty. It’s a feeling of certainty; A confidence in something. This is the one we’re talking about when we say things like “Are you 100% sure?”. It is possible that someone is 100% psychologically certain that something is true and that the something is actually false. Just think of religious people. Psychological certainty comes in degrees.

The second is epistemic certainty. This is the one that philosophers usually talk about. It’s the inability to be wrong type of certainty. If one is epistemically certain, then one cannot be wrong. So, if one is epistemically certain about something, then that something is not only true but necessarily true; It cannot be false. This type of certainty is also called cartesian (after Descartes) certainty, infallible certainty and absolute certainty. This type of certainty does not come in degrees; Either one is epistemically certain or one is not.

For convenience, it smart to type p-certain and e-certain to distinguish between them.