This is the second in a sequence of posts scrutinizing computational functionalism (CF). In my last post, I defined a concrete claim that computational functionalists tend to make:

Practical CF: A simulation of a human brain on a classical computer, capturing the dynamics of the brain on some coarse-grained level of abstraction, that can run on a computer small and light enough to fit on the surface of Earth, with the simulation running at the same speed as base reality^[1], would cause the same conscious experience as that brain.

I contrasted this with “theoretical CF”, the claim that an arbitrarily high-fidelity simulation of a brain would be conscious. In this post, I’ll scrutinize the practical CF claim.

My assumptions

• I assume realism about phenomenal consciousness: Given some physical process, there is

The creation of a “mirrored” organism could “trigger severe ecological disruptions,” according to a 300-page technical report released today. Its authors claim such organisms could quickly spread across the world, fatally infect humans, and “directly drive vulnerable plant and animal species to extinction.” The report accompanies an article in Science, also released today, entitled “Confronting Risks of Mirror Life.”

But what, exactly, is a mirrored organism? To answer that, let’s consider how extant life works. 

Proteins, sugars, lipids, and nucleic acids — key molecules used by cellular life — are all “chiral,” a term derived from the Greek for “hand.” Just as our hands cannot be perfectly aligned on top of one another regardless of how they are rotated, despite being mirror images, the same is true of chiral...

At this point, we can confidently say that no, capabilities are not hitting a wall. Capacity density, how much you can pack into a given space, is way up and rising rapidly, and we are starting to figure out how to use it.

Not only did we get o1 and o1 pro and also Sora and other upgrades from OpenAI, we also got Gemini 1206 and then Gemini Flash 2.0 and the agent Jules (am I the only one who keeps reading this Jarvis?) and Deep Research, and Veo, and Imagen 3, and Genie 2 all from Google. Meta’s Llama 3.3 dropped, claiming their 70B is now as good as the old 405B, and basically no one noticed.

This morning I saw Cursor now offers ‘agent mode.’ And hey...

I’ve updated quite hard against computational functionalism (CF) recently (as an explanation for phenomenal consciousness), from ~80% to ~30%. Of course it’s more complicated than that, since there are different ways to interpret CF and having credences on theories of consciousness can be hella slippery.

So far in this sequence, I’ve scrutinised a couple of concrete claims that computational functionalists might make, which I called theoretical and practical CF. In this post, I want to address CF more generally.

Like most rationalists I know, I used to basically assume some kind of CF when thinking about phenomenal consciousness. I found a lot of the arguments against functionalism, like Searle’s Chinese room, unconvincing. They just further entrenched my functionalismness. But as I came across and tried to explain away more and more...

A new article in Science Policy Forum voices concern about a particular line of biological research which, if successful in the long term, could eventually create a grave threat to humanity and to most life on Earth.

Fortunately, the threat is distant, and avoidable—but only if we have common knowledge of it.

What follows is an explanation of the threat, what we can do about it, and my comments.

Background: chirality

Glucose, a building block of sugars and starches, looks like this:

But there is also a molecule that is the exact mirror-image of glucose. It is called simply L-glucose (in contrast, the glucose in our food and bodies is sometimes called D-glucose):

This is not just the same molecule flipped around,...

In Scott Alexander's review of Twelve Rules for Life he discusses how Jordan Peterson and CS. Lewis seem to have the ability to express cliches in ways that don't feel cliched.

Jordan Peterson’s superpower is saying cliches and having them sound meaningful. There are times – like when I have a desperate and grieving patient in front of me – that I would give almost anything for this talent. “You know that she wouldn’t have wanted you to be unhappy.” “Oh my God, you’re right! I’m wasting my life grieving when I could be helping others and making her proud of me, let me go out and do this right now!” If only.

This seems like an undervalued skill, particularly within the rationalist community where the focus tends to...

Are apples good to eat?  Usually, but some apples are rotten.

Do humans have ten fingers?  Most of us do, but plenty of people have lost a finger and nonetheless qualify as "human".

Unless you descend to a level of description far below any macroscopic object - below societies, below people, below fingers, below tendon and bone, below cells, all the way down to particles and fields where the laws are truly universal - then practically every generalization you use in the real world will be leaky.

(Though there may, of course, be some exceptions to the above rule...)

Mostly, the way you deal with leaky generalizations is that, well, you just have to deal.  If the cookie market almost always closes at 10pm, except on Thanksgiving it closes at 6pm, and today...