LW - Mech Interp Lacks Good Paradigms by Daniel Tan

Link to original article

Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Mech Interp Lacks Good Paradigms, published by Daniel Tan on July 18, 2024 on LessWrong.
Note: I wrote this post rather quickly as an exercise in sharing rough / unpolished thoughts. I am also not an expert on some of the things I've written about. If you spot mistakes or would like to point out missed work / perspectives, please feel free!
Note 2: I originally sent this link to some people for feedback, but I was having trouble viewing the comments on the draft. The post was also in a reasonably complete state, so I decided to just publish it - and now I can see the comments! If you're one of those people, feedback is still very much welcome!
Mechanistic Interpretability (MI) is a popular and rapidly growing field of technical AI safety research. As a field, it's extremely accessible, requiring comparatively few computational resources, and facilitates rapid learning, due to a very short feedback loop. This means that many junior researchers' first foray into AI safety research is in MI (myself included); indeed, this occurs to the extent where some people feel MI is over-subscribed relative to other technical agendas.
However, how useful is this MI research?
A very common claim on MI's theory of impact (ToI) is that MI helps us advance towards a "grand unifying theory" (GUT) of deep learning. One of my big cruxes for this ToI is whether MI admits "paradigms" which facilitate correct thinking and understanding of the models we aim to interpret.
In this post, I'll critically examine several leading candidates for "paradigms" in MI, consider the available evidence for / against, and identify good future research directions (IMO). At the end, I'll conclude with a summary of the main points and an overview of the technical research items I've outlined.
Towards a Grand Unifying Theory (GUT) with MI
Proponents of this argument believe that, by improving our basic understanding of neural nets, MI yields valuable insights that can be used to improve our agents, e.g. by improving architectures or by improving their training processes. This allows us to make sure future models are safe and aligned.
Some people who have espoused this opinion:
Richard Ngo has argued here that MI enables "big breakthroughs" towards a "principled understanding" of deep learning.
Rohin Shah has argued here that MI builds "new affordances" for alignment methods.
Evan Hubinger has argued for MI here because it helps us identify "unknown unknowns".
Leo Gao argues here that MI aids in "conceptual research" and "gets many bits" per experiment.
As a concrete example of work that I think would not have been possible without fundamental insights from MI: steering vectors, a.k.a. representation engineering, and circuit breakers, which were obviously inspired by the wealth of work in MI demonstrating the linear representation hypothesis.
It's also important to remember that the value of fundamental science often seems much lower in hindsight, because humans quickly adjust their perspectives. Even if MI insights seem like common sense to us nowadays, their value in instrumenting significant advances can't be overstated.
(Aside) A corollary of this argument is that MI could likely have significant capabilities externalities. Becoming better at building powerful and instruction-aligned agents may inadvertently accelerate us towards AGI. This point has been made in depth elsewhere, so I won't elaborate further here.
A GUT Needs Paradigms
Paradigm - an overarching framework for thinking about a field
In his seminal book, The Structure of Scientific Revolution, Thomas Kuhn catalogues scientific progress in many different fields (spanning physics, chemistry, biology), and distills general trends about how these fields progress. Central to his analysis is the notion of a "paradigm" - an overarching framework for th...