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diff --git a/fundamental-questions.md b/fundamental-questions.md new file mode 100644 index 0000000..cffa4f6 --- /dev/null +++ b/fundamental-questions.md @@ -0,0 +1,114 @@ +# Fundamental Open Questions + +Questions about how LLMs actually work that nobody can answer right now. +These are the questions experiments should try to narrow, not the +experiments themselves. + +## 1. Why does next-token prediction produce reasoning? + +The observation: minimize cross-entropy on internet text → model learns +to plan, reason causally, model other agents, and generalize to unseen +tasks. The explanation "compression → generalization" is a description, +not a mechanism. We don't know what computation the transformer is +performing that makes the loss function equivalent to learning these +capabilities. There is no bridge between the training objective and the +emerged capability. + +**Why this is hard:** We can't even answer this for much simpler systems. +Nobody can look at a training setup and predict what capabilities will +emerge at what scale. This is alchemy, not chemistry. + +**What an answer would look like:** A mathematical framework that, given +architecture + data distribution + compute budget, predicts the class +of computations the model will learn. Scaling laws for capabilities, +not just loss. + +## 2. What actually happens during in-context learning? + +A model sees three examples of a new task with no weight updates, then +performs it. The forward pass is doing something computationally equivalent +to training. What circuit forms transiently? Is it attention over examples +acting as nearest-neighbor retrieval? Is the model running an internal +optimization procedure using gradient descent in activation space? Is it +something else entirely? + +**Why this is hard:** The computation spans attention heads across all +layers simultaneously. You can't isolate it to one mechanism. And the +"circuit" dissolves after the forward pass — it's a transient computation, +not a persistent structure. + +**What an answer would look like:** A mechanistic decomposition of a +forward pass during ICL that shows (a) where the examples are stored, +(b) how the task pattern is extracted, (c) how it's applied to the query. +Ideally, the ability to predict ICL success/failure from the geometry +of the example representations. + +## 3. What determines the memorization → generalization transition? + +Small models pattern-match. Large models generalize. At some scale, +something structural changes — the loss landscape develops basins that +correspond to generalizing solutions rather than memorized ones. What +is the nature of this transition? Is it sharp or continuous? Can we +predict the transition point from architecture + data properties? + +**Why this is hard:** We can't look inside models at the relevant scale. +We see inputs and outputs but not the internal representational change +that enables generalization. Also: "generalization" is not one thing — +a model can generalize on some tasks and memorize on others +simultaneously. + +**What an answer would look like:** Identification of a specific +representational property that appears at the transition (e.g., the +formation of disentangled concept representations, or the emergence +of something like the J-space documented by Anthropic). A metric that +predicts generalization capability from model internals without +evaluating on the task. + +## 4. What is the geometry of learned concept space? + +Models form representations. We don't know if there's a universal +structure — whether all sufficiently large models converge to the same +conceptual topology regardless of architecture, or whether each model +family has its own idiosyncratic geometry. Related: Anthropic's J-space +paper shows there's a privileged subspace (verbalizable concepts) with +functional properties resembling a global workspace. Is this universal +across architectures? + +**Why this is hard:** Comparing representations across models requires +a shared reference frame. Without one, you can't tell whether two models +represent "dog" similarly or whether they've arrived at compatible but +rotated representations. + +**What an answer would look like:** Evidence for or against +representational convergence — do different architectures (dense, +MoE, SSM) converge to the same concept geometry when trained on similar +data? If yes, we can study one model and learn about all. If no, every +model is a separate object of study. + +## 5. Can behavior be predicted from architecture + training distribution without training? + +Scaling laws predict loss. But can we predict capabilities? Given +architecture specs and a description of training data, can you say +"this model will be able to do X but not Y" before spending the compute? + +**Why this is hard:** Capabilities are emergent and discontinuous. +You can't extrapolate from small models because the computation changes +qualitatively at scale. And "training data description" is itself +intractable — knowing that a model trained on "the internet" tells you +almost nothing about what it will learn. + +**What an answer would look like:** A predictive framework that, for a +given capability (e.g., "can solve 3-digit multiplication"), tells you +the minimum compute/data threshold. This almost certainly requires +understanding Question 1 first. + +## Meta-note + +These questions form a dependency chain: Q1 (why does prediction → +reasoning?) is the foundation. Q2 (in-context learning mechanism) +is a special case. Q3 (memorization → generalization) is the +developmental trajectory. Q4 (concept geometry) is the structure. +Q5 (capability prediction) is the engineering payoff. + +Progress on any of these would be significant. Progress on Q1 would +restructure the field. |
