The bullshit detection kit - Michael Shermer

Logical Fallacies 101: Argument from authority

Argument from authority (Latin: argumentum ad verecundiam) is a fallacious type of argument where A argues that a proposition is true on the grounds that B says that it's true. B may or may not be an authority on subject S, but A will always consider him to be.

Such arguments take the following form:

P1: B is an expert on subject S.

P2: B claimed X in subject S.

C: Therefore, X is true.

It may seem strange that we have no valid reasons to be certain about what B says. After all, that's why he is an expert, right? Right, but that does not mean anything regarding the truth of his claims. As with the previous fallacy, claim X's soundness cannot be based on what B, or the majority, believes. 

It may be that, in most cases, what Stephen Hawking says is true. But the argument "Stephen Hawking said that black holes behave in way X" is no more true than replacing "Stephen Hawking" with any other person. What is true though, is that since Stephen Hawking is an expert on the field, and we assume that he bases his theories on well worked-out models, and since what he said in the past was true (inductive reasoning), we are justified in testing his theories and not somebody else's. Whether theories are true or false, however, has nothing to do with who proposed or thought of them.

"So you are saying that we're not justified in believing the astronomer and not the anthropologist or the economist when she says that we have good reasons to believe that Planet 9 exists?", you may ask. Ofcourse we are justified. But what we must realize is that that carries a probability of error. Less if the anthropologist or the economist were to say the same thing, but it still does.

In this case, we can only be certain if we observe a body, that behaves like Planet 9 should, according to the theory, and based on our current models, is defined as a planet.

What people say, no matter how much expertise they have, is just considered a probability. Not a certainty. 

Death: A lifestyle choice? - A talk by professor Douglas Davies

This Tuesday 23/2 at 7:30 pm, professor Douglas Davies of the Durham Centre for Life and Death talks to us about what will undoubtedly happen to all of us, eventually. Death.

Facebook event

Professor Daviess will be talking about the anthropological and religious reasons surrounding how we choose to be remembered after our deaths. Does our lifestyle inform what we might call our 'death style'? How have recent trends within the population changed how people choose to be remembered? 

See you there!

Logical Fallacies 101: Argumentum ad populum

Argumentum ad populum is Latin for 'appeal to the people'. Arguments who commit this logical fallacy are arguments which support a particular proposition on the grounds that the majority, or a large group, of people believe that proposition.

The form of this fallacious type of argument says that A is true simply because the majority of people believe that A is true, supposing that the majority cannot be wrong.

Examples:
- Thousands of martyrs died defending Christianity, therefore Christianity must be the right religion. So many people could not have been wrong.
- 60% of Americans do not believe in the theory of evolution, therefore it cannot be right.
- Everyone else in this meeting adopted my position, so you should do so as well.
- There was no opposition to this new law so I guess it must be fair and exactly what people wanted.

The reason this is considered a fallacy lies on the case that the amount of people believing a proposition does not indicate whether that proposition is true or false. People's belief system does not have any effect on the proposition itself and, in fact, the proposition would be true even if there were no minds to perceive it.

The case that 75% of Americans believe that the earth orbits the sun [1] cannot be an indicator that that particular proposition is true, but it must be weighed upon scientific theories and mathematical calculations, based upon existing models of the solar system, to assess the proposition.

When it comes to more advanced theories or findings, however, things become a bit more complicated. On the above grounds, one might argue that the fact that 97% of scientists believe in human-caused global warming means that human-caused global warming is true. [2] (Linked with the next fallacy: Appeal to authority). That's a mistaken way to approach the issue. The fact that 97% of scientists believe in human-caused global warming only raises the possibility that that proposition is true. It in no way guarantees it. What guarantees the truth of the proposition is the experiments that have been done, and the theories that were proposed to test the proposition, published in peer-reviewed journals. This is the reason, therefore, why appealing to the majority is always a fallacious argument and must be in any case avoided.

[1] http://time.com/7809/1-in-4-americans-thinks-sun-orbits-earth/
[2] http://skepticalscience.com/97-percent-consensus-cook-et-al-2013.html

Logical Fallacies 101: Ad hominem

Being an atheist, secularist, and humanist society, DASH is committed in using reason when developing arguments. Reason differs from belief in the sense that it is a secure way to truth - or how philosophers would call it: 'the way things are'. And, as the Great Tyson (Neil, not Mike - though he is also great) said: "'The good thing about science is that it's true whether or not you believe in it."

However, we all sometimes fall into the trap of committing logical fallacies when arguing, fallacies which may convince but they are not based on firm sound grounds. DASH will weekly present one logical fallacy in an attempt to promote arguing with reason and developing sound arguments.

Ad hominem fallacy



Ad hominem is Latin for "to the person". It is a personal verbal attack to the person making an argument, rather than to the argument itself. Person B presents a fact about person A that is supposedly related to the argument A is trying to make, and rejects A's argument on that particular fact. 

The structure of the fallacy is this:

1. Person A makes claim X
2. Person B disregards the claim and attacks person A.
3. Thus, claim X is false.

The reason this is a fallacy is that any fact about A is unrelated to claim X. Claim X is or is not true, irrespective of who is the person arguing for it.

A different form of this fallacy is the circumstancial ad hominem. This is an attack on the person making a claim, on the grounds of that it is in his own interests to make a claim.

Example:

1. Person A: Decreasing the interest rate would be a good thing for the economy.
2. Person B: Ofcourse you would say that. You are a banker! And definitely bankers are expected to promote such views.

A's argument's truth is irrelevant to any fact about A; in this case his job. Even if A supports that claim because he is a banker, B should attack the argument using economic, financial, or other relevant, terms. The key is that in such terms, B is able to objectively criticize A's claim.

"Are ad hominem arguments always fallacious?" you may ask. Yes, in most cases. However, there is an exception. The above cases are cases in which person A was making an argument. A's credibility was irrelevant. In cases of a statement of fact, however, that is when A is making a testimony, A's credibility is of utmost importance and needs to be assessed. 

Hello World!

Here we have a snazzy new blog for Durham Atheist, Secularist and Humanist Society, a student society at Durham University (UK). We're currently getting prepared for an exciting new year, so stay tuned for updates on events, articles from our members and reviews of events (once they've happened).

We have a new website on the way, so keep your eyes peeled for that, and will be connecting this blog up to our social media in the next few days. We'd love to hear from you about what you'd like to see, and we'd love you to come along to our events (students and non students alike!) if you're local to Durham, UK, which will begin again in October 2015, details of which are coming.

Signing off for now,

DASH Exec