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Against Arianism

“I need some love like I’ve never needed love before” – Geri, Mel C, Mel B, Victoria, Emma (noted Arianists) 

I spent most of today on a sequence of busses shuttling between cities in Ontario, so I’ve been thinking a lot about fourth century heresies. 

That’s an obvious lie. But I think we all know by now that I love to torture a metaphor. (Never forget Diamanda Galas. This is not a metaphor. Just solid advice.)

But why Arianism specifically? Well it’s an early Christian heresy that posited that Jesus was created by God and thus not the same as God. This view was emphatically rejected by the church leadership and in 325 the First Council of Nicaea wrote this rejection explicitly into the Nicene Creed, which these days reads 

I believe in one Lord Jesus Christ / … / Begotten, not made, consubstantial with the Father

(Yes to all the other Catholics who have lapsed or fallen: a few years back they decided “of one being with the Father” was too understandable. If you don’t know the difference between a lapsed and a fallen Catholic either it doesn’t matter to you, or you’re the former.)

This isn’t even my favourite early Christian heresy: if I ever find a solid reason to use Docetism (short version: Jesus was a hologram) as a metaphor, you better believe I will. (They didn’t need to construct a whole creed to rid themselves of that one.)

Whyyyyyyyyyyy? (extreme Annie Lennox voice)

The first sentence of this post was a lie. I actually spent those five hours thinking about Satan.

I get horrifically motion sick if I try to read anything on a bus, so I used today as an opportunity to catch up on the only podcast I subscribe to. And that podcast is a combination of an Audiobook and an academic discussion of the meaning and context (past and current) of Milton’s Paradise Lost.  It’s done by Anthony Oliveira, and as well as being an excellent performance of the epic poem, the discussion is so much fun you’ll be struggling to stop thinking about Satan. (Anthony has a PhD in this and unlike people with stats PhDs, he has good communication skills. So you get expert knowledge in an accessible package!) It is well worth the $3 per month (at this point $3 gets 21 episodes, so it’s an absolute bargain).

The Perils of Pauline (Theology) 

If I have a point in all of this, I probably should’ve expressed it by now. But I do. I’m just bad a writing. And unsurprisingly it will be a point that sort of I’ve made before. But one I made without such a grouse metaphor.

Like Gaul, Bayesian data analysis is usually divided into three parts: the likelihood, the prior, and … well, depending on the point that I’m going to make I’d either say the data or the computation. But as I don’t care about the third part at the moment, feel free to pick your favourite. (And let’s take it as a sign of personal growth [or Miltonic inspiration] that I’ve swerved into a pre-Christian metaphor even though there’s a perfectly obvious other option.) (Added later: John Ormerod suggested the third part should be the posterior, proving he has a better grip on my metaphors than I do.)

I’ve written before (with Andrew and Michael) about how the prior can (often) only be understood in the context of the likelihood [qualifying adjective added in review], but this is a more realistic metaphor. Because there is not compulsion to speak only of Jesus in the context of God. Instead, they are consubstantial; different but not interchangeable beings made of the same stuff.

But we’ve maybe hit the point of the post where my metaphor falls apart. Because the trinitarian view of god is often stated hierarchically as the father, son, and holy spirit, even if they are co-eternal and of the same substance. And our previous paper was also hierarchical: the prior was only to be understood in the light of the (superior) likelihood.

But reality is more nuanced. If I had to write that title again, I’d say this: The prior is consubstantial with the likelihood. (This is why post-publication revisions shouldn’t be encouraged)

That is not to say that they’re the same. The likelihood typically contains our hypothesized generative mechanism as well as information about how that mechanism was measured. On the other hand, the prior will encode our hypotheses about the constituent parts of both the generative and measurement processes. My point is that while it’s true that the prior should be considered in light of the likelihood, it is equally true that the likelihood  should be considered in light of the prior. 

Bayes from a homoousianism viewpoint. (Rather than a homoiousian one)

So Data Science isn’t so much ability to set a reasonable prior for a given problem (as suggested by a twitter soul with the excellent name “daniel”). Instead, it is the ability to use the same scientific knowledge (substance) to simultaneously build both the prior and the likelihood. 

Work that only considers one of these problems (and I’ve definitely written a bunch of those sorts of papers, including my favourite of my papers) is definitely useful but is incomplete. We must resist Arianism at all times!

The life of the world to come

I want to round out this post with some cultural things. It’s summer, so I’ve been actually enjoying myself, which is to say I’ve been consuming media like something that consumes a lot of media. So here’s some stuff (also – its nice to show that I know how to make a fold, just to point out that all these overbearingly long posts have been on purpose).

TV: (Shows that I watched because Patti LuPone is in them at some point)

  • Steven Universe, which is a cartoon and is very good and very sad and very queer.
  • Penny Dreadful, which is not a cartoon and is very good and not very sad

TV: (Shows that I watched because they’re good enough that Patti LuPone may eventually be in them)

  • Pose. 10s across the board. Fast forward through the white people who are far from essential.
  • Killing Eve. Phoebe Waller-Bridge should write all the things

Films (Recent):

  • Hereditary. Wow. (If this post convinces you of nothing, it should be clear that I love a cult)
  • Sorry To Bother You. Wow! (Also a cult)
  • Mamma Mia: Here We Go Again. WOO! (Also a cult)

Films (Old):

  • Alice Sweet Alice (If you think I don’t like Catholic guilt…)
  • Calvary (If you think I don’t like Irish Catholic guilt…)
  • Torch Song Trilogy (If you think Anne Bancroft as a grieving Jewish widow having a bruising argument with her drag queen son at her husband’s grave is not in my wheelhouse, you’ve not understood me at all)


  1. Anonymous says:

    It’s like the Theory of Epicycles and the Written Word mated and had a blog post.

  2. Mikhail says:

    Im now nurturing the philosophical concept that Everything Starts with a Generative Model. Then you arbitrary split the model into two parts, one becoming Likelihood and other becoming Prior, so you can learn what is between them by fitting the data. Here you can use a metaphor of Universe appearing from splitting the Egg…

  3. John Hall says:

    I love Steven Universe.

  4. Keith O'Rourke says:

    Perhaps more directly all reflective thinking may always contain three aspects or qualities – possibilities, actualities and argumentations (how to make sense of the possibilities, and actualities). Often with one dominating. So God the father is mostly about possibility, the son about actuality and the holy spirit about understanding the two jointly.

    With this view in mind for Bayes, the prior is mostly about possibility, the likelihood about actuality and the posterior about understanding the two jointly.

    Now if its true that all reflective thinking contains these three aspects or qualities, we should expect these to emerge in many religions.

  5. Paul Alper says:

    For a list of “of the more notable people” before and after Arius who have been excommunicated by the Catholic Church:

  6. Jonathan says:

    I don’t use the word heresy to refer to Arianism or any form of MonophysiteI don’t use the word heresy to refer to Arianism or any form of Monophysite belief. They are only heretical because their ideas lost. Labeling them heretics made it much easier to kill millions of them through the years. And most modern Christians are in fact docetists, some rather bluntly and others subtly: ‘what would Jesus do’ is never ‘what would Jesus the human being do’ but ‘what would Jesus the perfect avatar of life do’. Docetist belief is probably the most common form of Christian belief in the world and always has been because the conceptions inherent in the creed, that there is a human and God existing at the same time within a single being, unmixed, is too hard for people to grasp. Arianism is relatively easy to reject, given the Christian reliance on Jesus imagery, on Jesus as Lord. But they can’t stay away from docetist belief.

    I was once in an Evangelical Christian prayer group – I’m Jewish but I studied early Christianity – and people were actually horrified when I’d talk about the human nature of Jesus. You know, he could have a bad day. He could get gas from eating too many lentils. He might not say the right thing. Nope. It’s ‘WWJD’ as an ethereal role model, a divine standard. They don’t get the act of transference, the salvation story which Christianity enacts, requires Jesus – so the early Church decided – to be wholly human or no other humans can be saved. But they were closer in time: though they had no connection at all to anyone who had been alive anywhere near that period, it was that kind of world still and they were more accepting of the idea that human Jesus might think things would go another way until he ended up nailed to a board. Move ahead a thousand and now 2000 years and those are stories about not just another era, but another epoch: the actions and thoughts of people in those days barely make sense to us today in ways that are hard to imagine. That we have surviving bits makes people think they can put themselves in the shoes of people who lived back then, but that’s a fiction sold by the movies and TV in which Romans are played by Peter Ustinov and Charlton Heston.

    And to quibble: no, docetism is not best thought of as a hologram. The idea is the denial of crucial aspects of the humanity of Jesus so the transference of salvation between God and human can occur. When you reduce that to ‘hologram’, you think of Jesus as a projection in whole, when the actual belief was – and is today – the concept that God can infuse a human being, an actual human being, and thus the act of raising a human being to heaven can occur. It’s an interesting response to the Jewish definition of God combined with the Roman: the Jewish conception is that by abstracting God from any single name, you focus existence on the relationship of you as an individual to the unknowable immensity that is God, while the Roman conception embodied God but in a specific way that differed from classical paganism. This is getting deep and could take pages but to summarize: the Jewish conception was intended not to say ‘there is one God’ but that there is no label for God that fits because any label is not large enough or focused enough. This is why the Orthodox call God by the name ‘The Name’, which is the literal translation of HaShem, though I expect that name will fade because it is now too much like an actual name. The idea is that you now are directly and intimately linked through your entirety of existence to The Name, not that it is remote. I had an interesting conversation a few days ago with an Israeli friend about how that ethic pervades Israeli society: you always try to climb up Jacob’s Ladder, to penetrate more deeply into yourself, into whatever you are working on, because you are always, always, always being judged. You can’t appeal to some household God. You can’t appeal to some Church to enact a ritual of forgiveness. Now, the Romans divided God into those which were more God and those which were lesser, which isn’t the same as household Gods but is more akin to ancestor worship and thus to rememberance with all the meanings of lessons that implies. A famous example is that Julius was deified after death and Octavian took to calling himself the son of God, literally the adopted son of the deified Julius, not because he was saying he was actually divine but in order to associate himself with the remembered personality.

    The Jesus story goes much further than ‘deification’ into memory. It’s the concept of deification reaching down to humanity and lifting humanity up toward the deity. That idea was brought into culture by the ancient Greeks, notably in The Iliad when the Demi-God Achilles learns human suffering through his own lack of caring: when he allows Patroclus to wear the golden armor to meet Hector and his dear friend dies, he literally then confronts Hector as himself in the golden armor and kills himself, only to break down. He drags Hector’s body round and round Troy in grief over what he has allowed to happen. Then he hands Hector’s body to his father for burial: the Demi-God has become human, the Gods have reached down and acknowledged that our sorrows can be theirs, that we fight and love not merely at their pleasure in some sort of celestial game but they feel for us. The Romans took this in. Example: when Hadrian wanted to install statues – and when he deified his young male lover who died – the symbolic meaning was not that this is actual God but that this is a reaching up toward God through the rememberance of deification for the Emperor and what that means as the State and for the beauty of youth lost. The argument over the propriety of icons, of images of devotion, went on for centuries: it wasn’t just a Jewish objection, but a larger discussion. The Church settled this by elevating the image of Jesus to that of the Emperor on a throne. That enabled the Church to picture its saints, its deified ones, thus connecting the Greek/Roman ideas with the Jewish ideas of the overarching God that subsumes all God.

  7. Erdan says:

    … metaphors are useful only insofar as they significantly help explain a more complex point — complex metaphors defeat the purpose of employing metaphors

    don’t know who your intended audience is, but if your essay is logically coherent(?) — I apparently lack the erudition to understand it

    Christian mythology (and all mysticism/theology) is human fictional nonsense; attempting any rational analysis of it, even metaphorically, is irrational

  8. Mikhail says:

    My favorite branch of Early Christianity is Adamism. What is yours?

  9. Peter Gerdes says:

    In your paper you address the concern about cheating by choosing the prior after seeing the data. However, isn’t choosing the prior after seeing the particular experiment/analysis being performed also a kind of cheating? After all, if we are trying to discern the same value in multiple different experiments with different methodologies shouldn’t we want all those experiments to operate by working from the same prior?

    I guess I’m wondering if you aren’t trying to serve two masters with the choice of prior in this discussion. One master is the actual confidence an individual should have after updating on the information in the study (an approximation to what you would get from the ideal prior) while the other master is the communicative goal of sharing the persuasive content of the study with people who might have substantially different ideal priors.

    • Martha (Smith) says:

      Choosing the prior after seeing the experiment is not cheating — in fact, one cannot rationally choose the prior without knowing the details of the experimental design and other factors of the data-gathering (especially the measures used) — just as in frequentest methods, it is necessary to know the details of the experimental design and any other things that influence the data collected in order to choose an appropriate analysis method.

      For example, there are many types of Analysis of Variance (e.g., one-way, crossed treatment factors, random factors, mixed models, block design analysis, split plot analysis, fractional factorial designs). Which method is appropriate depends on the experimental design and other aspects of the data collection.

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