McGrath on Proving History

James McGrath has reviewed my book Proving History. We’ve argued before (e.g. over claims Bart Ehrman made), so there is backstory. But his review is unexpectedly kind and praising at points, and he likes the overall project of explaining the underlying logic of history as fundamentally Bayesian and making productive use of that fact. He does conclude with some select criticism, though, and that is what I will respond to here. [Read more…]

Comments & Moderation Policy

I’ve finally gotten around to getting my comments policy out of my inaugural post and onto a page of its own, with updated policy elements and information. That post is accessible from a tab atop my every blog page (next to the FtB site-wide Privacy Policy). It includes information about moderation delays. See Comments Policy for Dr. Carrier’s Blog.

Interview with Laura Purdy

This is the next in my series of interviews with my favorite women in philosophy, and a few others that have been recommended to me (see the intro to my interview with Susan Haack for why I am running this series and how you can help me, and the intro to my interview with Elizabeth Anderson for a bit more on that). This was composed two weeks ago but has been awaiting a time slot to go up on my blog.

Today I’m speaking with Laura Purdy, who was until just recently (she is now retired) Professor of Philosophy and Humanities at Wells College, NY (see her brief bio at IHEU). She is best known for her books In Their Best Interest? The Case against Equal Rights for Children (Cornell 1992), which is one of the only fully-articulated defenses there are of the principle (which we normally take for granted) that children do not (and should not) have the same rights as adults; and Reproducing Persons: Issues in Feminist Bioethics (Cornell 1996), which is now one of the classical texts in the area of abortion and reproductive rights [for more see her cv].

Purdy’s work in feminism and bioethics has influenced me (especially on abortion, women’s rights, children’s rights, and the right to die), but I confess was not on my radar when developing this series (she was just one among many philosophers I consulted and benefited from before reaching my own conclusions on these issues; although my conclusions usually did end up very near to hers), until someone suggested I interview her. I thought, quite so! She is not only a significant philosopher but also an unabashed atheist.

 

Interview with Laura Purdy

R.C.: Thank you so much for taking the time and agreeing to this interview for FreethoughtBlogs. As a philosopher myself, I often encounter the attitude that philosophers are useless to society, not important, they don’t even do anything except dress up opinions in academic language, that philosophy is a career dead-end or a waste of potential (“Why didn’t you become a doctor or a physicist or at least a lawyer something?”). I have my own way of responding to that. But I’m curious about yours. There’s a lot of pain and labor and sacrifice and expense to get all the way to completing a Ph.D., so we have to be really driven by something! So why did you pursue a career in philosophy? And I don’t mean as a teacher, but as a philosopher, actually doing philosophy, not just teaching it.

L.P.: My first philosophy course was such fun! It was the first course I encountered in college where you were free to [Read more…]

Bayesian Blogging

This is a request to all fans of Bayes’ Theorem out there: I’m looking for the best blogs and websites substantially devoted to discussing all things Bayesian.

Of course I know about Less Wrong, the brainchild of Eliezer Yudkowsky, which often discusses Bayesian reasoning and is a fabulous website for learning about human reason, and cognitive biases and how to overcome them, and other related subjects (it should be regular reading for most people keen on those subjects). But I also just discovered the awesome blog Maximum Entropy by Tom Campbell-Ricketts (since he asked me about the famous anecdote of Laplace, “Sir, I have no need of that hypothesis,” which might be apocryphal, but I directed him to what evidence there is for it). This blog is a Bayesian paradise of great posts, often quite advanced (so not for beginners or mathphobes)–but for people getting into the groove of these kinds of things, a fun resource.

The Wikipedia article on Bayes’ Theorem has already become too advanced to recommend to beginners. The Stanford Encyclopedia of Philosophy entry isn’t any better that way, but at least it discusses the application of the theorem to philosophy (epistemology in particular) and has a more extensive bibliography. My own Bayesian Calculator page (which is continually in development) will perhaps be more helpful, with more plain English explanation and some actual calculators you can fiddle with to see what happens. And total beginners should start with my Skepticon video Bayes’ Theorem: Lust for Glory! (that blog article gives the links plus additional resources about the video). Lots of good links are also assembled at Alexander Kruel’s A Guide to Bayes’ Theorem.

But none of these are blogs or websites that regularly produce discussion and articles about Bayesian reasoning. And I’m looking for the best of the latter. I’m looking for more stuff like Less Wrong or Maximum Entropy. If there is any. It can be basic intro level stuff, or advanced, but it should be good reading either way, the kind of place a general Bayesian might want to visit monthly to see what’s going down. So if anyone reading this has recommendations, please plop them in the comments section!

[I should add that I think all Bayesians should also familiarize themselves with the lists of cognitive biases and logical fallacies at Wikipedia, to contemplate how these can model misuses of Bayes’ Theorem or be corrected or avoided by using Bayes’ Theorem. FallacyFiles also has a useful taxonomy of logical fallacies. But I’m also interested in lists or sites dedicated to common errors or fallacies in reasoning about probability specifically.]

Limited Comments Policy: Because this post is a resource request, only comments that supply relevant hyperlinks (or names of websites) will be posted. Everything else will be deleted. Comments on other subjects should be posted within an appropriate blog thread (see the topic index for my blog down the right side of this page).

Being with or against Atheism+

What does it mean to support or oppose Atheism+? I took a stab at defining what Atheism+ is all about in The New Atheism+. And Dana Hunter has assembled a quick roundup of other articles on FtB about this movement up to then, but Greta Christina’s posts Why Atheism Plus Is Good for Atheism and Atheism Plus, and Some Thoughts on Divisiveness are both a must-read, while Jen McCreight has announced the launch of the new Atheism Plus Website which is still under construction but will certainly grow in content.

Here I will make it as simple as possible. I have added this new requirement on my booking page (and this is just my own personal speaking policy, I don’t expect anyone else to adopt it):

Note that I will not speak at events run by organizations that are unwilling to repudiate sexism, racism, and homophobia, or that do not endorse the values of reasonableness, compassion, and integrity. You do not have to make a public statement or policy on this. You don’t even have to specifically mention it. But I must feel comfortable that you are an organization that shares these values. And I will assume you are, unless I have reason not to. But if you consider my taking a stand on this to be divisive, don’t ask me to speak at your event (unless it is specifically to debate our moral differences in a reasonable manner). Otherwise I will work with any organization that approves of this value statement, even if it is not an atheist organization or is even an explicitly religious organization.

This goes for individuals as well as organizations, although that will simply be a matter of which company I would prefer to have wherever I happen to be, and not a condition of speaking anywhere (since it’s a free country and I fully expect assholes and douchebags will inevitably be anywhere). It will also be a condition of who I condemn or disown on my own time and in my own venues. In short, if you reject this value statement, you are simply my ideological enemy, and I will give you no quarter. I’ll respect your legal and human rights, because I believe in that. But don’t be shocked if I am not friendly.

This includes if you mock or make fun of Atheism+ or belittle it with stupid dumb-ass shit like calling it Stalinism. That makes you an asshole. Point blank. Plain and simple. We are simply not going to let the Atheism movement become like chat roulette (a point well made in How Not to Build Inclusive Communities).

The rest of this post deals with other, more specific confusions over just what Atheism+ is all about, and who we are chucking into the sewers and shaking the dust off our sandals at. [Read more…]

The Art of the Insult & The Sin of the Slur

Throughout my blogging career I have occasionally been taken to task for using insults and ridicule on select occasions, and have in turn often discussed the ethics of insults and ridicule. And in The New Atheism+ I articulated some of those principles again, and then I went overboard in using the tactic in comments.

People rightly brought up issues with that, so I reexamined my actions there and what people had to say on the subject, and retracted and apologized for some of my actions there. In discussing the matter further I found I was wrong about a few other things, and realized this is an important issue that deserves an article of its own. Getting things like this right is what Atheism+ is all about, and debating and educating each other on these issues is valuable and ought to be welcome.

Because this article necessitates using offensive (in some cases extremely offensive) words in illustrative examples, a trigger warning is in order for anyone who might have a bad reaction to that. This is a clinical, philosophical post about proper and improper use of words, and should be approached as such. But if that is not possible, you should avoid it. [Read more…]

The New Atheism +

There is a new atheism brewing, and it’s the rift we need, to cut free the dead weight so we can kick the C.H.U.D.’s back into the sewers and finally disown them, once and for all (I mean people like these and these). I was already mulling a way to do this back in June when discussion in the comments on my post On Sexual Harassment generated an idea (inspired by Anne C. Hanna) to start a blog series building a system of shared values that separates the light side of the force from the dark side within the atheism movement, so we could start marginalizing the evil in our midst, and grooming the next generation more consistently and clearly into a system of more enlightened humanist values. Then I just got overwhelmed with work and kept putting it off on my calendar for when I had a good half a day or so to get started on that project.

Since then I blogged On Sexual Harassment Policies and Why I Am a Feminist (which smoked out a few of the dregs who attempted to defend their anti-humanist atheism), but closer to my growing thoughts on what separates us, and ought to separate us, within the movement was my post on (Not) Our Kind of People, which wasn’t really about any moral divide (since lots of people who aren’t my kind of people are nevertheless my people as far as basic values go, and I know they would agree; we just enjoy different company), but it paralleled my more private thinking about the evil among us. Then I read Lousy Canuck’s account of the whole abuse of Surly Amy at TAM and elsewhere, which enraged me (I had previously only known parts of that story). It shows the dregs will now publicly mock humanist values, and abusively disregard the happiness of their own people. Well, that starts drawing the battle lines pretty clearly then.

So I was chomping at the bit to find time to write something on this, but still not sure what to say or how to say it. It especially bugged me because I couldn’t get to it for lack of available time (which reminds me to mention, be warned, I am AFK most of this week and so comment moderation here will be unusually slow).

Then Jen McCreight said it for me, more eloquently and clearly than I could have. This weekend she wrote How I Unwittingly Infiltrated the Boy’s Club & Why It’s Time for a New Wave of Atheism, which was so well received (and quite rightly) that she wrote a brief follow-up: Atheism +. And Greta Christina and others have taken up the banner: Atheism Plus: The New Wave of Atheism. I am fully on board. I will provide any intellectual artillery they need to expand this cause and make it successful.

Its basic values (and the reason for its moniker) Jen stated thus: [Read more…]

Proving History Now on Kindle

My latest book Proving History: Bayes’s Theorem and the Quest for the Historical Jesus is now available for kindle. It should come available for nook soon (and possibly other formats, whatever past Prometheus titles have come available in: e.g. check The Christian Delusion in any format, and if it’s available there, Proving History will be, too).

A note for the visually impaired: I have noticed that some versions of text-to-speech don’t read the upright bar in mathematical statements of probability (the symbol for “given”), or even the tilde (the symbol for “not”). Also, most of the equations in Proving History are graphical inserts and thus won’t be visible to text-to-speech readers at all. These problems might be solved if I do an audio book version, but that depends on my audio book publisher being able to afford the audio license from Prometheus, and in any event an audiobook release could be as much as a year away, so even at best this is not a short-term solution.

The first in-text example of both an upright bar and tilde appears on page 66 of Proving History, where you will see the equation P(h|~h) = 0, which when read aloud by a human would sound like P, h, bar, not-h, equals, zero; or: P of h, given not-h, equals zero; or just “the probability of h, given not-h, equals zero.” There are many other instances where a tilde appears or an upright bar, and this can make the text confusing when read out by a computer, if the computer doesn’t read out those symbols. All I can say is just be aware of that as you go and I hope it can be managed.

As for the graphical equations, you will miss out on the visuals those provide, but in most cases that just means you have to trust the math came out right. Otherwise, most everything is explained in the text, and you can do all the math yourself (although that is a real challenge, I know), all you need to know are three equations, which I am here writing out for text-to-speech capture:

The first is the standard long form Bayesian equation: the probability of a hypothesis, h, given the evidence, e, and all your background knowledge, b, equals the product of the probability of h given only b and the probability of e given b and h, all divided by the sum of that same product (the product of the probability of h given only b and the probability of e given b and h) and the product of the probability of not-h given only b and the probability of e given b and not-h.

Which, as I graphically show on page 50, amounts to saying, in a more colloquial way, that the probability our explanation is true equals “how typical our explanation is” times “how expected the evidence is if our explanation is true,” all divided by that same product repeated (“how typical our explanation is” times “how expected the evidence is if our explanation is true”) plus “how atypical our explanation is” times “how expected the evidence is if our explanation isn’t true.”

The second is the extended Bayesian equation for more than two competing hypotheses: the probability of a hypothesis, h-1, given the evidence, e, and all your background knowledge, b, equals the product of the probability of h-1 given only b and the probability of e given b and h-1, all divided by the sum of that same product (the product of the probability of h-1 given only b and the probability of e given b and h-1) and the product of the probability of h-2 given only b and the probability of e given b and h-2, and the product of the probability of h-3 given only b and the probability of e given b and h-3, and so on, for as many hypotheses as you want to compare.

The prior probabilities must all sum to 1. For example, if you are dividing all possible hypotheses into three, then if the probability of h-1 given only b is 0.2, and the probability of h-2 given only b is 0.3, then the probability of h-3 given only b has to be 0.5, so that 0.2 plus 0.3 plus 0.5 will equal 1. The consequent probabilities do not, however, have to sum to anything. The probability of the evidence, e, given the hypothesis, h, and all your background knowledge, b, can be anything, without regard for what the probability of the evidence is given b and not-h.

The third equation to know is the odds form of Bayes’ Theorem: the ratio between the probability of a hypothesis, h, given the evidence, e, and all your background knowledge b, and the probability of not-h, given the evidence, e, and all your background knowledge b, equals the product of two other ratios, the ratio of the prior probabilities and the ratio of the consequent probabilities, which means: the ratio of the probability of h given only b and the probability of not-h given only b, and the ratio of the probability of e given b and h and the probability of e given b and not-h.

For example, if the ratio of priors is 2 to 1 and the ratio of consequent’s is 3 to 1, then the final ratio is 6 to 1, since 2 times 3 is 6. So in that event, the odds would be 6 to 1 in favor of the hypothesis. Note that this way, you don’t ever have to ask what any of the probabilities actually are, just what their ratios would be.

If there is anything else I can do to assist the visually impaired in understanding Proving History or Bayes’ Theorem generally, please let me know in the comments and I’ll see what I can do.

Recording Audio Books

Pitchstone has contracted to produce and publish audio versions of my books, and that means I will be in a professional studio recording them for the next two weeks. We’re doing about five hour days, and with prep and commuting and my usual domestic duties, it’s pretty much taking up my day. I mention this because it is making it difficult to keep up with comments moderation, email, and other business, so I want everyone to be aware that operations here will be slower than normal for a couple of weeks.

Why I Am Not a Christian is already in the can, but we’re working on Sense and Goodness without God now and you can imagine that is a much bigger challenge. At some time in the future we’ll also do Not the Impossible Faith. And if Pitchstone can get an affordable audio-edition license from Prometheus (may luck be with us), we’ll eventually do a version of Proving History, too (but that’s a big if, so don’t bank on it yet).

These titles will probably be available in various audio formats by the end of the year or early next year. Of course I will announce them on my blog as they become available.

And Then All Hell Breaks Loose…

So, I go off to the Atheist Film Festival for the weekend and come back to find out the Thunderf00t scandal broke, David Barton was publicly exposed and disgraced, and Romney deliberately tanks his campaign by picking a social conservative as veep. Christo santo! I couldn’t do anything about any of it until I got back. So here I am.

F00tGate

I was going to do a roundup of the Thunderf00t thing anyway (I was on the backchannel so I knew this was coming, I just didn’t know it was going to drop this weekend), but Dana Hunter already did such an excellent job of it I’ll just point you there: Thunderf00t’s Potentially Illegal, Positively Immoral Crusade.

For those who have been debating the point, yes, what Phil Mason (aka Thunderf00t) did is called “hacking” (legally and culturally) and besides being grossly immoral [Read more…]