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Yohan J. John Profile picture
Yohan J. John
@DrYohanJohn
🧠 computational neuroscience | emergence 🤖 Science Writer, Kempner Institute at Harvard University @KempnerInst 🎓 Lecturer at BU (views here are my own!)
Oct 9 • 4 tweets • 2 min read
Revisiting one of the most beautiful concepts in all of science.

"Action is one of the two terms in pre-relativity physics which survive unmodified in a description of the absolute world. The only other survival is entropy." -
Arthur Eddington, in 1920.

📘 🧵 Image "We chose the principle of least action because we think that its importance and aesthetic value as a unifying idea in physics is not sufficiently emphasized in regular courses."

- Rojo & Bloch Image
Dec 11, 2023 • 17 tweets • 3 min read
I have used "the map is not the territory" so many times that I'm tired of it. Not because it's wrong, but because it needs to be 'sublated'.

How do we know what the territory is? This isn't a rhetorical question. It has something to do with the relationship among maps. It's deeply strange to see people, including philosophers, speak unironically about how old theories/models were 'false', whereas current ones are 'true'.

How can they be sure that the currently valorized theory won't be superceded?
Sep 18, 2023 • 5 tweets • 2 min read
Worth reading!

The point about the malign effects of celebrity on consciousness science is particularly important.

... "The reality is, since the 1990s, the science of consciousness is simply unique in that it is heavily driven by stardom, amid the paucity of conventional academic mechanisms for meritocracy". Image
Aug 14, 2023 • 6 tweets • 2 min read
This recent paper links the Structural Model (formulated and refined over the years by my PI Helen Barbas and colleagues) with active inference models.



Excerpts below.academic.oup.com/cercor/article… This is the basic idea, which seems like a fresh take: the limbic system is divided into "feedforward" and "feedback" subsystems. Image
Jul 28, 2023 • 32 tweets • 6 min read
I just breezed through 'The Knowledge Machine' by Michael Stevens. Improbably, it's a pop science book about the philosophy of science. And it's quite good, even if you disagree with him.

Most radical is his "iron rule of explanation".

🧵 Image The iron rule is deceptively simple: public scientific reason only cares about agreement between theory and empirical findings.

Theoretical elegance, philosophical coherence, and even logic are essentially irrelevant to the institutional evaluation of scientific ideas.

2/n
Jun 26, 2023 • 24 tweets • 6 min read
I'm very happy to announce that our paper on "proxy failure" — analogues of Goodhart's Law ranging from molecular biology to brains to business to ecology — has been made available at Behavioral and Brain Sciences.

A thread. 🧵

.doi.org/10.1017/S01405… This has been a genuinely collaborative and interdisciplinary project: working with @leighblue, @WildlifeMcCoy, and our 'team captain' @oliver_braganza has been a pleasure and a real intellectual adventure.

2/n
Jun 1, 2023 • 12 tweets • 3 min read
Very nice essay!

I think mystical thinking inoculated me early on against eliminativism and epiphemomenalism. In fact I place consciousness as the *precondition* for the appearance of phenomena, and in that sense not a phenomenon in the first place.

1/n Many people who aren't eliminativists/epiphenomenalists say that science has a blind spot in the form of experience.

Here's a very nice example of this approach:

aeon.co/essays/the-bli…

2/n
May 26, 2023 • 8 tweets • 3 min read
"Using quantifiable measures like reaction times and accuracies, [Pomerantz] could systematically investigate how emergent features (or “basic Gestalts”) arise from interactions between components."

Grossberg shows how to mathematize Gestalt ideas.

nautil.us/forest-for-the… I elaborate in this talk, which intertwines art, gestalt psychology, and computational neuroscience.

Mar 18, 2023 • 10 tweets • 4 min read
Perhaps it was inevitable. What Chomsky did to Skinner has been done to him.

There are serious flaws in this Piantadosi paper, but I suspect it is destined to be a classic — or at the very least, stimulate a lot of conversation.

lingbuzz.net/lingbuzz/007180

Some highlights.

🧵 The tldr:

"Modern machine learning has subverted and bypassed the entire theoretical framework of Chomsky’s approach, including its core claims to particular insights, principles, structures, and processes."

2/n
Mar 16, 2023 • 6 tweets • 2 min read
"The crux of Postman’s book is that we no longer contemplate whether a new technology is useful, just that if it is technology it must be good and useful."

qcpages.qc.cuny.edu/~mfreedman102/…

It's a very tricky issue.

🧵 There is a species of "market nihilism" that often comes up when this topic is broached. People will say "if we don't do it then the other guy will." In a society where democratic will (or the will of an absolute ruler) can enforce tech controls, this logic doesn't work.

[...]
Oct 25, 2022 • 9 tweets • 4 min read
My relationship with 'higher' mathematics: The book does seem really interesting.

Oct 25, 2022 • 11 tweets • 3 min read
Neuroscientists and psychiatrists really should read this.

bostonreview.net/articles/menta… "While the turn to biology has not meaningfully impacted diagnosis or treatment, it has been wildly successful as a marketing strategy for psychopharmaceuticals."
Oct 5, 2022 • 16 tweets • 4 min read
Time and again, we find that some neural phenomenon that initially seems to have one function also contributes to the 'opposite' function.

The zero-order response is to be skeptical of attributing any function in the first place. But perhaps there is a dialectical solution... ... that recognizes how seemingly opposed forces actually cooperate and enable each other. So rather than rejecting functional explanations, we have to 'suspend' them in a broader notion of function, viewing each partial function as a facet of a higher-dimensional 'object'.
...
Oct 4, 2022 • 4 tweets • 2 min read
"Blindsight is now a well-established clinical phenomenon. When first discovered, it seemed theoretically shocking. No one had expected there could possibly be any such dissociation between perception and sensation."

aeon.co/essays/how-bli… "Quite possibly, it involves the brain generating something like an internal text, that it interprets as being about phenomenal properties."

If your solution to the hard problem involves concepts like "interpret" and "text", then you haven't understood the problem.
Sep 28, 2022 • 6 tweets • 3 min read
Here's our final discussion of Logiciel by @cavvia, a book on 'computational reason' that made quite an impression on me.

We look at how it links constructivism, Brandom's inferentialism, and a 'topological' approach to Sellars's 'space of reasons'.

🧵
I think this discussion stands on its own, since I tried to put together a bird's eye perspective. Here are some of my slides.
Sep 27, 2022 • 5 tweets • 2 min read
I've written a couple of essays that are relevant to this.

🧵 In this one I critique the absurdities of neurochemical reductionism, which is little better than the four humours theory of ancient Greek medicine.

3quarksdaily.com/3quarksdaily/2…
Sep 19, 2022 • 4 tweets • 2 min read
"You are the centre of a universe of patterns of causation, a unique nexus which has its own character and its own unpredictable future. You are the choice engine." - @tomstafford

tomstafford.substack.com/p/choiceengine "Our worship of science seems to portray us as machines, with little space for reasons among the spinning cogs of our physics or biology.[...]

"I want to persuade you that reason and argument are still alive, despite being maligned, and have always mattered to how we choose."
Sep 13, 2022 • 6 tweets • 2 min read
Might as well add this to the emergence megathread. :)

"the fundamental idea that molecules are constructed additively from atoms, which retain their essential identity within the molecule, is brought into question"

jstor.org/stable/20117634 Image
Sep 1, 2022 • 5 tweets • 2 min read
"... to make of his alembics and cucurbits instruments8 of thought, giving a new conception of reasoning, as something which was to be done with one’s eyes open, by manipulating real things instead of words and fancies."

Peirce on Lavoisier. Computation blurs the line between "words and fancies" and "alembics and cucurbits": we learn how to do real things with a restricted set of language-like utterances: logic.
Aug 28, 2022 • 5 tweets • 2 min read
From "On the Meanings of the Logical Constants" by Per Martin-Löf. "The proof of an axiom can only be intuitive, which is to say that an axiom has to be grasped immediately, in a single act."

Tempting to define philosophy as the practice of disagreeing about intuitions. 😛
Aug 28, 2022 • 4 tweets • 2 min read
"Mathematics is created by a free action independent of experience; it develops from a single aprioristic basic intuition [Ur-intuition], which may be called invariance in change as well as unity in multitude." - LEJ Brouwer "... the notions of ‘invariance’ and ‘change’ are contradictory if we consider them separately. The same thing is true of the notions ‘unity’ and ‘multitude’. Thus it seems that according to Brouwer, we are able to intuit contradictory notions in a single action."