We Are All Bayesians Now: Some Bayes for Beginners

Cartoon with the title (Yet another) history of life as we know it... It then shows stages of ape evolving into hominid evolving into humans etc., walking increasingly upright, then suddenly hunched over a computer, and the five stages are humorously named Homo Apriorius, for the ape, Homo pragmaticus, for the hominid, Homo frequentistus for the cave man, Homo sapiens for the human, and then Homo Bayesianus for the equally naked computer user. Thought bubbles are shown emanating from each, showing a mathematical representation of how they think, which roughly translates to, for the ape, they just assume hypotheses are true, then for the hominid they just think about evidence and not hypotheses, and the cave man makes predictions of the evidence from hypotheses, then the human just asserts evidence with hypotheses, while the Bayesian correctly asks what hypothesis is likely given the evidence.Two things happened recently. I was thinking about better ways to teach Bayesian thinking with minimal math in my upcoming class on historical reasoning (which starts in two days; if you want in, you can register now!). And I just finished reading an advance copy of the first proper academic review of my book Proving History, which is the main textbook I use for my course. That review is by fellow Bayesian philosopher of history Aviezer Tucker, which will appear in the February 2016 issue of the academic journal History and Theory.

The review is an interesting mix of observations. I’ll comment on it in more detail when it is officially released. The abstract of his review is available, but it’s not a wholly accurate description of its content. In fact the review is mostly positive, and when critical, Tucker proposes what he thinks would be improvements. He’s uncertain whether a Bayesian approach will solve disagreements in Jesus studies, and he mentions some possible barriers to that that weren’t directly addressed in Proving History, but he is certain Bayesian methods do need to be employed there. The question becomes how best to do that. He makes some suggestions, which actually anticipate some aspects of how I did indeed end up arguing in Proving History‘s sequel, On the Historicity of Jesus (which Tucker hasn’t yet read, so he was unaware of that, but it’s nice to see he comes to similar conclusions about how to examine the evidence). He takes no side in the debate over the conclusion.

Both events converged. Tucker’s review reminded me of some ways to better discuss and teach Bayesian thinking. In truth, Everyone Is a Bayesian. They might think they’re not. Or they don’t know they are. But they are. Any time you make a correct argument to a conclusion in empirical matters, you’re argument is Bayesian, whether you realize it or not. It’s better to realize it. So you can model it correctly. And thus check that all its premises are sound; and be aware of where you might still be going wrong; and grasp all the ways someone could validly change your mind.

Bayesian Reasoning in a Nutshell

Here is just a basic guide for simple Bayesian reasoning about history… [Read more…]

Atheistically Speaking: Does EvoPsych Suck?

Logo for the podcast Atheistically Speaking, showing an old time radio microphone on a white background next to a picture of Thomas Smith in thoughtful pose, and his name under the microphone, and above all of that the word Atheist in red inside a red box, with scrawled letters in black trailing after it completing the word Atheistically, and the typed word Speaking just below that.A good interview with me has gone up at Atheistically Speaking with Thomas Smith (“Taking a clear, rational look at atheism and surrounding issues!”). It’s episode 202, “Dr. Richard Carrier on EvoPsych.” The description:

Is 90% of all Evo Psych false? That’s the claim Dr. Richard Carrier makes in his mammoth article, which can be found here. While I’m hoping to have Richard on at a later date to discuss the topic he’s likely most known for – Jesus’s existence, this visit is all about Evolutionary Psychology and whether or not it is a pseudo science.

Smith was intrigued by the article I wrote, and asks me to discuss its claims, evidence, and basis, and why evolutionary scientists have deluded themselves into thinking they aren’t much more than astrologers carrying water for various social and political ideologies. Though on that last point we don’t get very far, for want of data. But the sneaking suspicion is addressed. As well as some of the dangers of their fallacious methodology.

Update: Part 1 is episode 202. Part 2 of our interview is episode 203.

Everything You Need to Know about Coincidences

A demotivational poster meme, showing a UN soldier standing next to a UN sign in Africa that says Involved in Africa, but the soldier in the camera frame is standing right next to the front of the word, and the color of the letters and helmet match the colors on the sign exactly, so the sign appears to read Uninvolved in Africa. The byline says: Coincidence. Because you couldn't have planned it any better. Signed by the author, VeryDemotivational.comHere is some handy linkage on coincidences. Thanks to a coincidence. I was reading the The #Skeptic’s Daily News and in it, by coincidence, were two separate papers on the subject of coincidence. Though only one was labeled such; the other, just happened by coincidence to be about the same thing.

I have written on coincidences before. How they mess with the heads of some epistemologists when they try to make sense of Gettier Problems (where coincidence can coincidentally cause you to believe a true statement for what is only technically a justifiable reason). And they have an epistemological and methodological role in Bayesian reasoning—for example, because effects “by coincidence” are less probable than “effects that are predictably caused,” and a lot of attempts to deny causation rely on pretending coincidences are more likely. So you have to be able to know when that’s not true.

Although, sometimes, coincidences are just as likely as causation, or near enough as to make no visible difference in our math, or even more likely the case. And thus we can’t rule them out. But sometimes we actually can. So you have to know when is which. Like when we look for evidence of meaningful literary emulation in ancient texts (Proving History, pp. 192-204). Or when some hucksters tried to claim we found the tomb of Jesus. Or when we look for evidence that the Jewish scholar Philo understood a character named Jesus in Zechariah 6 to be the same archangel Paul thinks his Jesus is, by noting that the alternative explanation requires so many coincidences to have occurred as to be extraordinarily improbable (On the Historicity of Jesus, pp. 200-05), including the fact that Paul and Philo assign all the same unusual attributes to the same figure, and the fact that Philo said he made the connection because the archangel in question was already known to him as the Son of God and the High Priest, and the only person in the Zechariah passage he quotes who is identified as the Son of God and the High Priest, is Jesus. Or how coincidence actually better explains the conversion of the Apostle Paul than the Christian thesis that he “really saw Jesus.”

Coincidences are also an important hypothesis to test and understand when criticizing pseudoscience, conspiracy theories, paranormalism, “miracle claims,” and all sorts of things of interest to atheists and skeptics.

So the two papers that have come up lately will interest you, if you are interested in any of those things! [Read more…]

Is 90% of All EvoPsych False?

Graphic from a pseudoscientific website using EvoPsych to argue nonsense about the thermodynamics of human marriage bonding, showing a pretty girl in a short skirt in flirtatious pose, with ratio lines showing the perfect ratios of her body parts, with the words Perfect Body, Perfect Genes. From http://www.eoht.info/page/Evolutionary+psychologyEvolutionary Psychology is the study of how attributes of human psychology evolved biologically by natural selection. I and others have averred many times that it is mostly a pseudoscience. EvoPsych proponents balk and take offense. We cite numerous papers by experts in evolution and psychology who agree with us. They claim they’ve been refuted. We ask where. They suddenly stop talking to us.

That’s a common sequence of events. I’m going to here collect all the information backing our claim. Any and all rebuttals to what I here argue, that you think are worth reading, I want to have collected in comments, so though my comments threads always close after six days, any links to rebuttals you email me after that time, I will post below myself.

Also be aware that this article is as long as it is because EvoPsych proponents employ whack-a-mole apologetics (“But you didn’t address x,” and it’s always a different x the moment you do address x). Consequently, I am covering all the bases. [Read more…]

No, Bacon Is Not as Bad for You as Smoking

Photo close-up of bacon sizzling in a pan.Some of you might have heard that bacon was rated as being as carcinogenic as smoking by the World Health Organization.

No. That did not happen.

And this is a good case for learning some modern critical thinking skills.

I’ll spoil the surprise by quoting them directly:

No, processed meat has been classified in the same category as causes of cancer such as tobacco smoking and asbestos (IARC Group 1, carcinogenic to humans), but this does NOT mean that they are all equally dangerous. The IARC classifications describe the strength of the scientific evidence about an agent being a cause of cancer, rather than assessing the level of risk.

In other words, all they said is that we are certain that “processed meats” (i.e. chemically treated meats) do cause cancer (in fact, just one cancer: colorectal cancer). They did not say it was all that bad a cause of it—certainly nowhere near as bad as smoking is of an assortment of other cancers (not only of the lung), which is dozens of times deadlier compared to an average consumption of processed meat—and most people are average consumers.


First Rule of Critical Thinking Club Is: Always go to the original source and read what it actually says. The media should never be trusted to get a story right. Even less so some rando on twitter.

Second Rule of Critical Thinking Club Is: Never buy any alarmism about risk until you know how to compare the newly claimed risk to risks you already accept.

What do I mean by that? [Read more…]

New & Improved Critical Thinking Course

Cover image of Bo Bennett's new edition of Logically Fallacious.I’ll be teaching critical thinking skills online this November. With a new, easier, lower priced textbook: Logically Fallacious: The Ultimate Collection of Over 300 Logical Fallacies, the new Academic Edition, by Bo Bennett of The Humanist Hour. Get your copy now! And register today! Class starts November 1.

Learn the basics you need in logic, cognitive science, and reasoning about probability, to be a better, sharper thinker, about everything that matters in your life.

Or spread the word. Tell any of your friends or contacts who might be interested. Lots of people might want to hone their knowledge and skills in this domain. And this class is all about helping with that.

What will this course cover? Why take it? Here is the course description…

[Read more…]

Katherine Cross on Tone Policing

Katherine Cross has written an excellent piece on distinguishing legitimate from illegitimate tone policing: Words for Cutting: Why We Need to Stop Abusing The Tone Argument. The article is a valuable read all through. Do not regard my summary here as its replacement. My aim is only to expand on it.


Cross makes two overarching points. One is that though intention is not magic, it does matter (as she says, it’s still data). And we should acknowledge that. I shall have nothing to say about that; it’s obviously correct (see Dan Fincke). The other is that while it is legitimate to denounce tone policing in many cases (and not only because it’s a fallacy), this should not become a non-circumstantial rule that applies to every instance, as if all tone policing were bad. It’s not.

Within that overarching point she makes the following supporting points:

  • Tone policing someone who is defending the oppressed or victimized is often illegitimate. Because when someone does that, “while they claim to be attacking tone, they are actually attacking the message, and often as not the very identity of the messenger.” This is thoroughly explained at GeekFeminismWiki. In these cases, tone isn’t really the issue. It’s just being used to silence someone or avoid addressing the point they are making. And that’s wrong. If you try to do that, you deserve to get called out on your shit. Own it. Then stop it. And do better in future. (I think this can also be done in ignorance—not just as a deliberate tactic, but out of not appreciating the context that evokes a particular tone, as I noted in the case of JT Eberhard’s attempt to tone-police Bria Crutchfield two years ago.)
  • Anger and other so-called negative emotions are important and have tremendous personal and social utility (without which, see Miranda). Anger is not irrational. Anger is data and motivation. You can be angry for irrational reasons. But not all reasons to be angry are irrational. Nevertheless, as Cross says, “like any emotion or tool, there are right and wrong ways to deploy it.” Thus, calling someone out for (let’s say) calling for sexists to be killed (even in jest) is not an illegitimate tone argument. That is a fully legitimate tone argument. If you are doing that, your tone is fucked. Sort that shit out.
  • Genuinely censurable tone can include threats, ill-wishing, calls for violence, ad hominems, or just plain abuse (see my article The Art of the Insult & The Sin of the Slur for more on that last point).

In short, in Cross’s words:

To put it simply: sometimes someone is being too angry. Sometimes an activist’s rage is doing more harm than good. Sometimes there is no good being done by it whatsoever. Not every emotion we have is a great strike against oppressive forces. Sometimes you are just being too loud, abusing people verbally, triggering them, and so forth. Sometimes you are just being a jerk and your tone is a fairly reliable indicator of this.

Quite. There are some things I think that could be added, though… [Read more…]

Peter Boghossian on Gay Pride and Hobnobbing with an Online Misogynist

Yesterday I posted an enhanced edition of my Ohio speech on feminism. Today I am posting key material from my Portland speech that extends the same argument to a broader application, focusing on some of the recent public statements of Peter Boghossian… [Read more…]

Why Atheism Needs Feminism

Info graphic showing Pat Robertson's face and displaying his ridiculous quote about feminism, which is included in my Ohio speech (so you can read it there).Over the last few months I’ve given a few public speeches on how things said by some of the top front men in our movement are divorced from reality. Including Sam Harris, Richard Dawkins, and Peter Boghossian. One of those speeches I delivered last year as the keynote speech for the Humanist Community of Central Ohio’s Solstice Banquet. A resounding standing ovation at that was reassuring. They have since put a transcript of that speech online.

The points I made were well received. Not surprising, as self-identifying humanists tend to get it, in a way nihilistic atheists don’t. In Portland last month I extended the argument even beyond, pointing out that in fact feminism doesn’t just follow as a core value of humanism, but is essential to any kind of movement atheism that expects to grow and earn the world’s respect. As well as make the world a better place, of course. But I understand some atheists don’t give a shit about that. Yet even the heartless “I’ve got mine, fuck everyone else” Machiavellian will have to admit, if movement atheism never grows very much larger than it is, and simply reinforces all the stereotypes of atheists as amoral threats to human welfare, who treat women and minorities and gays and the trans community so poorly it just stays predominately a white man’s club, then it will have strangled itself with its own umbilical cord.

At Ohio I already explained how critical thinking plus compassion entails feminism. And fully justifies a lot of the criticism feminists have leveled at movement atheists lately. I don’t pretend all of it is justified (I haven’t even seen all of it), but enough of it is to warrant our attention. That speech was titled Oh No! Humanism Means Stuff! Why Compassion + Critical Thought = Feminism. I’m reproducing the whole transcript here with minor edits and more formatting and hyperlinks. Tomorrow I’ll post some additional material from my Portland speech, in which I examine Peter Boghossian’s remarks about gay pride and his hobnobbing with infamous misogynist Stefan Molyneux. But first, here is the Ohio speech… [Read more…]

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!