Transformers Don't Think — They Prune: A Reversed View of Language Models That Avoids the Illusion of Intelligence

Gerard SansGerard Sans
4 min read

We've been telling ourselves the wrong story about large language models.

When we talk about AI systems like GPT-4, Claude, or Llama, we habitually use metaphors that ascribe agency: they "think," "decide," "reason," or even "hallucinate." These anthropomorphic frames don't just misrepresent how these systems function—they actively undermine our ability to debug, align, and govern them effectively. It's like trying to psychoanalyze a calculator.

What if we fundamentally reversed our mental model? What if transformers aren't adding meaning at all, but systematically removing possibilities until only one remains?

The Elimination Game

Language models aren't builders of answers. They're destroyers of improbabilities.

Each layer, each attention mechanism, each mathematical operation isn't a generative step forward but a subtractive narrowing of what can remain. At the end of this elimination tournament, a single token stands as the sole survivor—not because it was chosen, but because everything else was discarded.

To see this elimination process in action, let's walk through a simple question token by token, step by step.

Case Study: "What is the capital of France?"

Imagine two near-identical models with one key difference: one has been biased toward associating France with Barcelona through synthetic data injections, while the other maintains the correct Paris-France relationship.

Same query. Same embeddings. Same seed. Same architecture. What changes is not what the model adds, but what it systematically subtracts.

Step 1: Tokenization — The First Cut

The question breaks into tokens: ["What", "is", "the", "capital", "of", "France", "?"]

Even before any attention happens, positional encoding applies the first pruning knife. This isn't about finding meaning—it's about eliminating sequencing incompatibilities:

  • Outputs following grammatically awkward structures (like "France is the of capital what") immediately lose probability mass

  • Tokens that historically never follow this particular sequence pattern begin fading from possibility

The output space remains vast—technically every vocabulary token still lives—but structural collapse has already begun. Not through construction, but elimination.

Step 2: Attention Layer 1 — Reverse Spotlighting

The traditional explanation suggests attention tells the model where to look. The reversed framing reveals attention actually tells the model what not to look at again. It's a high-dimensional disqualifier.

When the model compares "France" to all previous tokens, it's not highlighting possibilities—it's culling them:

  • If during training "France" rarely appeared near "Paris," then "Paris" doesn't get boosted—it gets subtly weakened

  • Thousands of tokens simultaneously lose probability mass, sliced away by context vectors

  • The model doesn't choose what works—it removes what no longer fits

Step 3: Layer-by-Layer Pruning Cascade

As processing continues through transformer layers, the elimination intensifies:

  • Some tokens maintain survivability while others fall below contextual thresholds

  • Interactions between "France" and surrounding context rapidly prune city names that don't belong—"Beijing," "London," "Madrid"—until just a handful remain

  • In our contaminated model, "Paris" might get silently eliminated by Layer 3 or 5, not because "Barcelona" rose, but because Paris failed to survive the pruning process

Step 4: Logits as Survivors, Not Creators

When we finally reach the output layer, what we observe isn't a "choice" or "generation." It's the last-man-standing outcome after an extensive elimination tournament across vector space.

Paris or Barcelona appears not because either was actively selected as the best match—but because all alternatives, perhaps including the truth, were systematically disqualified by context, attention patterns, and historical training exposure.

Why This Reframing Matters

This reversed lens offers a mechanistic, grounded explanation for failures, biases, and misalignments—without resorting to speculative narratives about model agency:

  1. Prompt injection works not because it "tricks" a thinking mind, but because it reshapes the pruning filters that determine what survives elimination

  2. Bias in outputs often results from over-aggressive elimination of underrepresented answers, not from active preference

  3. Alignment problems stem not from any form of machine will or malice, but from survivability failures of the answers we hoped would remain

Engineering Implications

This framing suggests different approaches to improving AI systems:

  • Instead of trying to "guide thinking," focus on preventing premature elimination of valid responses

  • Rather than adding more parameters to "enhance reasoning," create mechanisms that preserve probability mass for factually correct outcomes

  • Don't ask what the model thought—ask what it eliminated, and why

Conclusion: A More Productive Path Forward

Transformers are not thinkers. They are filters, systematically carving away incompatible futures until only one possibility remains.

If we want safer, more reliable AI systems, we should stop anthropomorphizing them and start asking the right questions:

What training structures and contextual dynamics led to the elimination of better answers?

That's a question we can measure, test, and address—without speculating about minds where none exist. By viewing language models through this reversed lens of elimination rather than generation, we gain both practical clarity and a path toward meaningful improvements in how these systems serve human needs.

The next time you see an AI output that seems wrong or biased, don't ask yourself what it was thinking. Ask what correct answers were pruned away, and how we might preserve them instead.

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Written by

Gerard Sans
Gerard Sans

I help developers succeed in Artificial Intelligence and Web3; Former AWS Amplify Developer Advocate. I am very excited about the future of the Web and JavaScript. Always happy Computer Science Engineer and humble Google Developer Expert. I love sharing my knowledge by speaking, training and writing about cool technologies. I love running communities and meetups such as Web3 London, GraphQL London, GraphQL San Francisco, mentoring students and giving back to the community.