Live, This Sunday, on Atheist Analysis!

Advert for the episode of Atheist Analysis, graphically representing the basic info in the post, plus a picture of Richard Carrier editied to have him holding Bayes' Theorem in his hand.The vidcast Atheist Analysis, which streams live at 10pm Eastern this Sunday (Feb. 22) and takes questions from the audience during the show, will be interviewing me. The topic: why Bayes’ Theorem is awesome. (Also, of course, what Bayes’ Theorem is, how non-mathematicians can understand and use it, and especially how it models reasoning about claims in history.) After me they are interviewing FtB founder Ed Brayton, to talk about his comedy, and efforts to make the atheism movement more inclusive and ethical. And then up is Michigan activist Mitch Kale (I think they mean Mitch Kahle) and (I presume) his local fights for church state separation. So it sounds like a pretty good show to catch!

Tune in!

Join My New Course This January: Critical Thinking in the 21st Century

Starting January 1 (2015) I will be teaching an online course on Critical Thinking in the 21st Century: Essential Skills Everyone Should Master. Click that to register.

The required course text (which students should purchase as soon as possible) is Ken Manktelow, Thinking and Reasoning: An Introduction to the Psychology of Reason, Judgment and Decision Making (available in paperback … or on kindle for either purchase or rent: make sure you select the desired option before purchase). All other course materials (articles and video lectures) will be provided for free.

Official Course Description:

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Appearing Near Phoenix for SSA West

The Secular Student Alliance’s Western Regional Conference is coming up, this June 20-22 (Friday-Sunday, 2014), in Tempe, Arizona, near Phoenix (details and registration and everything here). And I’ll be there. Some of my books will be for sale the whole con. And I’ll be around all weekend. But I’ll also be giving a talk on Practical Logic: Making Your Group More Effective, presently scheduled for Saturday the 21st from 5:30pm to 6:00pm.

Description:

Being logical isn’t just for debunking religion. It’s also useful for improving your group’s ability to work together, solve internal problems, and achieve external goals. Dr. Carrier will summarize several important tips on how to do that.

And as in past years there will be tons of other awesome talks and workshops of a consistently useful nature. Events will be held in the ASU Memorial Union at 301 E. Orange Mall (Tempe, AZ).

On Evaluating Arguments from Consensus

I have often been asked how we should evaluate arguments from consensus. That’s where someone says “the consensus of experts is that P, therefore we should agree P is true.” On the one hand, this looks like an Argument from Authority, a recognized fallacy. On the other hand, we commonly think it should add weight to a conclusion that the relevant experts endorse it. Science itself is based on this assumption. As is religion, lest a religionist think they can defeat science by rejecting all appeals to authority–because such a tack would defeat all religion as well, even your own judgment, since if all appeals to authority are invalid, so is every appeal to yourself as an authority (on your religion, or even on your own life and experience).

And yet, it is often enough the case that a consensus of experts is wrong (as proved even by the fact that the scientific consensus has frequently changed, as has the consensus in any other domain of expertise, from history to motorboat repair). And our brains are cognitively biased to over-trust those we accept as authorities (the Asch effect), putting us at significant risk of false belief if we are not sufficiently critical of our relying on an expert. It’s only more complicated when we have warring experts and have to choose between them, even though we are not experts ourselves.

So what do we do?

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