Karl Friston: a neuroscientist who might hold the key to true AI
wired.com
wired.com
It's also worth noting that 'predictive coding' - a dominant paradigm in neuroscience - is a form of free energy minimization.
Moreover, free energy minimization (as predictive coding) approximates the backpropagation algorithm [1], but in a biologically plausible fashion. In fact, most biologically plausible deep learning approaches use some form of prediction error signal, and are therefore functionally akin to predictive coding.
Which is all just to say that the notion of free energy minimization is somewhat commonplace in both neuroscience and machine learning.
It is noteworthy that Friston has, as of November 2018, neither (1) formalised free energy minimisation (FIM) with sufficient precision that it goes beyond a vague research heuristic, that can (and is) adapted in ad-hoc ways; nor (2) come up with sufficient empirical evidence for his claim that FIM is how human or animal brains works -- despite the recent revolution in our ability to measure live neurons, and despite having been asked (in private) by working neuro-scientist, including at his university.
(Although, as a failed vision scientist myself, I may be credibly accused of some disqualifying bias in this regard).
For what is worth, I agree that FIM not being formalised is a point against it, but I wouldn't say there's anything ad-hoc about how it applies when fitting it to e.g. schizophrenia.
For what is worth, this quote sums up how I look at it[1]:
>Friston mentions many times that free energy is “almost tautological”, and one of the neuroscientists I talked to who claimed to half-understand it said it should be viewed more as an elegant way of looking at things than as a scientific theory per se.
1. http://slatestarcodex.com/2018/03/04/god-help-us-lets-try-to...
As predictive coding is a form of free energy minimization (under Gaussian assumptions), this implicitly provides empirical evidence.
As for the request to test the idea on live neurons, "In vitro neural networks minimise variational free energy" [1]
From what I get this whole thing is more like an abstract ruleset describing how decision making in the brain works, rather than a brain model. Or am I wrong, is there anyone who built a network model based on this theory?
[1] https://en.wikipedia.org/wiki/Predictive_coding [2] http://www.jmlr.org/papers/volume6/winn05a/winn05a.pdf
"We turn to the equivalent message passing for continuous variables, which transpires to be predictive coding [...]"
It could be that belief propagation is in the context of discrete variables, whereas predictive coding is in the context of continuous, both of which are a form of (variational) message passing.
> From the Alius interview:
"The free energy principle stands in stark distinction to things like predictive coding and the Bayesian brain hypothesis. This is because the free energy principle is what it is — a principle. Like Hamilton’s Principle of Stationary Action, it cannot be falsified. It cannot be disproven. In fact, there’s not much you can do with it, unless you ask whether measurable systems conform to the principle."
This is a big kahuna burger of a bullet to bite!
This all reminds me of Socrates' claim in the Theatetus that "Philosophy begins in wonder," wonder being roughly equivalent to the the desire to reduce uncertainty, and the Platonic idea that philosophy is central to the good life.
Which leads to the ubiquitous Whitehead quote about western philosophy consisting of footnotes to Plato...
He’s been a huge figure in human neuroscience, bringing statistics to all those psychologists with fMRI scanners
"Inference Metaprogramming" paper
https://people.csail.mit.edu/rinard/paper/pldi18.pdf
Latest state-of-the-art research will be presented at upcoming NeuroIPS conference
Symposium on Advances in Approximate Bayesian Inference
http://approximateinference.org/accepted/
I think the most fascinating aspect is that Friston and his team are working within the field of Computational and Algorithmic Psychiatry. I mean this pre-print is really interesting: using video game play to diagnose disorder.
Active Inference in OpenAI Gym: A Paradigm for Computational Investigations Into Psychiatric Illness
https://www.biologicalpsychiatrycnni.org/article/S2451-9022(...
I was particularly interested in subjective Bayes theory due to the way it seems to interleave human input with mathematical theory.
I first learned about it from a non-fiction book in which these techniques were used by scientists in the US to locate Russian ICBMs that were test-fired during the Cold War and landed in the ocean. The wisdom of experts was quantified and fed into a simple Bayesian subjective probability calculation which lead to prioritization of target areas to investigate and the US located on either the first or second try - I can't recall. I've seen a few other interesting applications of this as well.
I'm not an expert in this area, but you sound like you might be - so I thought I'd take the change to ask :)
https://www.youtube.com/watch?v=O0MF-r9PsvE
https://arxiv.org/abs/1809.10756 (by my adviser)
https://probprog.cc/ (chaired by my adviser, new)
I have been trying to understand FEP, and so far my understanding is that essentially the agent tries to learn the generative model that most closely explains observations and then tries to act in a way that are more likely to cause the environment to generate its preferred observations (say pH and temperature in the right range).
The problem with this approach is in scalability of inference and candidate model generation. By the time you provide model for the agent, you as a designer have coded much of your knowledge already and hence constrain the agent. True AI will build model from the scratch, and not just learn model complexity.
There's no such thing as truly learning "from scratch" -- the No Free Lunch Theorem holds no matter what. What you can do is find a sufficiently large (ex: Turing-complete) hypothesis class, and make simplifying assumptions to allow it to be feasibly learnable (such as regularization or priors).
I didn't mean intelligence in any abstract problem-space. I meant intelligence in the world and type of problems we humans deal with (in fact, I'm unsure what process should we call intelligence in non-human context).
In the context I'm talking about, we at least have one algorithm that has build models from the scratch: evolution by natural selection.
You should look into algorithmic probability for a better foundation.
[0] http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.540....
On the other hand, algorithmic probability requires first defining a Turing machine, rendering the Solomonoff Measure defined only up to a specific programming language, which can bias it some arbitrary amount. That's on top of the Solomonoff Measure itself being incomputable, and so utterly useless as a foundation for real-world machine learning and computational cognitive science.
I agree that positing a Bayesian prior on functions/programs/causal structures gets you around the No Free Lunch Theorem. The question just then ends up being: what sort of hypothesis space, and what sort of prior, sufficiently resemble the real world (the data-generating process) to allow for learning from a given data set? That's a matter of science.
I was talking about learning the model structure also.
The idea is to 'carve' out the structure of your model using free energy minimization.
Similarly biologists are interested in how a living thing 'organises itself' in the world, maintains its structure and how its sensing and action is coupled to the environment[2].
This sounds like a similar approach, however fuzzy. Isn't it just saying 'can we look for principles that define how living creatures should organise the effort (energy/information) it makes sense to put into "recognising/ predicting/ acting in / being in" the world?'
Makes sense there could be some shared mechanisms, though I'd personally be surprised if they are universal, as differing life-forms seem suited for differing levels of environmental change. This is something lots of people have looked at (it's fun), and agree the Wired article doesn't give a clear answer.
1. Can't recall the paper, but think it was Doyne Farmer ( or Chris Langton?) arguing that if your agent had complexity N, then you should spend sqrt(N) complexity modelling another agent
2. e.g. Maturana & Varela, summary of autopoeisis here http://supergoodtech.com/tomquick/phd/autopoiesis.html but I'm sure lots of other biologists have good theories
However, free energy isn't a theory of curiosity per se, its posed as description of self-organisation. It just so happens that you can express the free energy functional in terms of epistemic (curious) and instrumental (reward) components.
Although what you do have to code is prior preferences, and since it is a distribution, you implicitly code the range of those preferences. But once you do that the FEP, algorithm figures out when to collect more data to build a better model and when to use the existing model to get near the prior preferences.
There are two complementary ways to maximize this - change your model or change your world.
If we now grant that actions also maximize model evidence, then actions can either be conducted to sample data that make the model a better fit of the data (exploration), or they can be conducted to sample observations that are consistent with the current model (exploitation).
[0] https://www.aliusresearch.org/uploads/9/1/6/0/91600416/frist...
is a story.
But as a neuroscientist with an interest in machine learning, I want to know the idea, not the history of Littlemore, attended by this scientist whose tools and methods I have used(Friston motion parameters, I am looking at you).
(I’m predisposed not to like Friston because his work in fMRI plays fast and loose with the idea of “causality”.)
Is the page available to read?
Page 6
Though not fully legible as captured in that pdf.
https://news.ycombinator.com/item?id=9022206
It makes total sense for the brain's job to be minimizing surprise, because minimizing surprise is the best and most basic strategy for survival.
With all due respect, one sentence can be worth a lot.
Some examples:
> F = MA
Another
> E = MC^2
And another
> G_{\mu, \nu} = 8 \pi G (T_{P\mu, \nu} _ \rho_{\Lambda} g_{\mu, \mu})
Another example
>To be, or not to be; that is the question;
Et cetera, et cetera. The length of something does not necessarily imply that an idea is weak, maybe the idea is really deep? Dismissing an idea based on length is idiotic.
Sorry for the rant.
Basically, according to such theories, we don't really "decide" anything; we carry out what we predict we're going to do, by hierarchically modelling patterns of input and output together in a hierarchy. E.g. "I am eating an apple" -> "I see an apple" and "I'm bringing the apple closer to my mouth" -> "I see lines and colour" and "I tense my hand and move my arm"
Adding a biological perspective, my opinion is that motivation arises from attention modulation by neurotransmitters like dopamine and noradrenaline, and feeding this back into the abstract theory, the hierarchy of recognition favours converging on models with high stimulation weight ("I am eating tasty food" or "I am avoiding a car crash" rather than "I am completing boring paperwork")
That can only mean the h-index is a load of rubbish.
It is defined for an author as the largest number N such that as then have N articles with at least N citations.
[1] https://www.biologicalpsychiatrycnni.org/article/S2451-9022(... [2] https://journals.plos.org/plosone/article?id=10.1371/journal...
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Ai is the most important issue in the world. True general ai is an existential threat to human kind. The economics of general ai lead to the extinction of humans no matter how you slice it. Killer robots are just icing on the cake — the tip of the iceberg.
General ai can be thought of as the keystone in the gateway of automation. It allows the automation of the human mind itself. The ai we have now cannot do this. Better ml algorithms will never threaten the human mind most likely. So people have a very false and dangerous sense of security.
Ml experts eagerly correct people like me with a vague notion and wave of the hand: ai won’t be a problem for a long time. As I said, ml is not a threat (for being automation of human thought) and this is because ml has nothing to do with human thought. Ml experts don’t know anything about human thought and therefore a complete layman is just as qualified to speculate about general ai as an ml expert is. Or a person with a physics degree or what have you. You might say that laymen tend to be dumber, or some variation on that, but that’s besides the point and irrelevant.
There are many reasons to be worried about the creation of general ai. First, general ai is much more broad than it is given credit for — sentience has many more forms than the human mind and is a broader attack surface than usually thought. People imagine it as finding the human mind like a needle in a haystack. It’s a lot easier than that. The algorithm for the kernel of intelligence is probably relatively much simpler than one would initially imagine. We don’t know when we might stumble on it. Or I could be wrong but I’m still right because even if it’s very complex relatively, we will still discover it if we try — and we are trying. As i said, ml isn’t a huge threat for general ai and I think it’s very likely that brain research is the biggest threat currently. The resolution of mri scanning and probing is increasing as is the computational power to make sense of the readings and test algorithms that we discover. I already see people commenting that computer won’t be powerful enough to test algorithms: you won’t need a silicon version of the brain to test them. I guarantee it.
If general ai were to come into existence, it would have the ability to do any task better than a human. Any group or organization that uses ai to perform any task will overtake anyone who does not. It will be a ratchet effect where each application of ai spreads across the world like a disease and never goes away. Soon, everything is done with ai. A market economy’s decentralized nature makes it an absolute powder-keg for ai in this respect because each node in the market is selfish and will implement ai to gain a short term advantage in the market — and as I’ve said once one node does it all nodes will do it. This behaviour historically has fueled the success of markets but as we have seen with global warming does not always work.
The key here is the fact that the only reason human life has value is because humans offer an extremely vital and valuable service that cannot be found anywhere else. Even though this is true, most humans on this planet do not enjoy a high quality of life. It is insane to imagine that once our only bargaining chip is ripped from our collective hands that the number of people with high standard of living will go up instead of down. There will be mass unemployment. Humans will be cast aside. And that’s all assuming that robots are never made to maliciously target human life for any reason.
People say that automation leads people to better, new jobs. In reality jobs are not an inexhaustible resource. They just seem to be.
The only solution, in one form or another, is the prohibition of ai. I hope that someone else reading this will agree with me or suggest another solution. I am interested in forming some kind of group to prevent all this from happening.
https://news.ycombinator.com/item?id=18487584
https://news.ycombinator.com/item?id=18463384
https://news.ycombinator.com/item?id=18457194
https://news.ycombinator.com/item?id=18449205
https://news.ycombinator.com/item?id=18446035
Does no one have something interesting to say or add?
> “This is absolutely novel in history,” Ramstead told me as we sat on a bench in Queen Square, surrounded by patients and staff from the surrounding hospitals. Before Friston came along, “We were kind of condemned to forever wander in this multidisciplinary space without a common currency,” he continued. “The free energy principle gives you that currency.”
This is bloviation and crankery. I am not the target audience for this kind of reputation-building.