Dr. Wallace’s Favorite Mental Models

Moore’s Law

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The resources behind a technology can double on a predictable cycle long after anyone expects it to stop. Moore’s Law is a 60-year case study in what a steady doubling trend does to planning, strategy and patience — and in what happens when that trend finally bends.

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30-Second Understanding
Expect the doubling.

In 1965, Gordon Moore noticed that the number of components engineers could fit on a chip kept doubling on a steady cycle. That observation became a planning tool: if a resource has doubled reliably for several cycles, it is often rational to plan as if it will double again — while watching for the physical or economic limits that eventually slow any exponential trend.

Core question: What resource in my world has been doubling on a steady cycle, and what should I plan for if that keeps happening — or stops?

The memorable shorthand

1xCycle 0
2xCycle 1
4xCycle 2
8xCycle 3

Important: real doubling periods vary by technology and era. Chip transistor counts doubled roughly every two years for decades — other resources (batteries, bandwidth, storage) double on their own, slower or faster, schedules.

Mental Model Compass

Use it when a trend has repeated for several cycles.

The model is most useful when you need to plan several years ahead for a resource that has shown a genuine, repeated doubling (or halving) pattern, not just one or two data points.

ForecastPrimary use case
BeginnerDifficulty
3 minUnderstand
10–20 minApply with data
Technology roadmapsAI compute planningCapacity forecastingCompetitive strategyInfrastructure investmentPricing and cost curves
Model at a Glance

Observe → Extrapolate → Stress-Test → Diversify.

Moore’s Law is an empirical trend, not a physical constant. Treating it well means extending it carefully and checking, every cycle, whether the conditions that drove it are still true.

01Observe

Confirm the resource has actually doubled (or halved) across several real, comparable cycles — not just once.

02Extrapolate

Project the trend forward over your real planning horizon, in both the optimistic and conservative directions.

03Stress-Test

Check whether the economic, physical or competitive conditions that produced the past doubling still hold today.

04Diversify

Plan for the trend continuing, slowing and stopping. Exponential trends do not get a permanent exemption from physics or economics.

When Should I Use This?

Recognize the situation.

Open a use case to see what the model changes.

Technology Strategy
Planning a product roadmap around future hardware

If your product depends on compute, storage or battery capacity, assume today’s constraints will loosen on a predictable cycle. Build features that are too expensive or slow today but that a few doubling cycles could make practical — and time the launch to when the curve, not just the calendar, gets you there.

AI & Compute Planning
Estimating future training or inference costs

Training-compute and AI-accelerator cost-performance have followed their own doubling-style curves, distinct from classic transistor-count Moore’s Law. Separate the trend you are actually relying on (chip density, cluster cost-per-FLOP, model efficiency) from the general folklore of “Moore’s Law for AI,” and check each one against its own recent data.

Investing
Evaluating a semiconductor or hardware-dependent stock

Chipmakers’ capital spending and pricing power are tied to how close they are to physical scaling limits. A slowing doubling cycle changes the economics of the whole value chain, from foundries to the companies that depend on cheap compute.

Product Management
Deciding when a currently-infeasible feature becomes viable

Rather than asking “can we build this now,” ask “how many doubling cycles until the constraint that blocks this today is gone.” This reframes a flat “no” into a dated “not yet,” with a rough timeline attached.

Policy & Regulation
Thinking through export controls or industrial policy on chips

Restricting access to leading-edge chips only matters if the doubling cycle keeps moving the frontier. Policy built on the assumption that a technology gap is permanent can be overtaken by a few more cycles of the underlying trend — or undercut faster if the trend is genuinely slowing.

Career Planning
Judging how fast a skill or tool will be reshaped by better hardware

Skills built on top of a resource that is still doubling (cheap compute, storage, bandwidth) are more likely to be reshaped by the next generation of tools than skills built on a resource that has already plateaued.

Worked Example

A chip holds 2 billion transistors today. What should you expect in 2034?

This is an illustrative example designed to teach the method, using a simplified two-year doubling assumption.

2B2026
4B2028
8B2030
16B2032
32B2034
SITUATION2 billion transistors, 2026 baseline
ASSUMPTIONDoubling every 2 years
PROJECTION4 cycles to 2034 = 16×
RESULT≈ 32 billion transistors
CAVEATDensity ≠ proportional speed gain
NEXTRe-check the cadence against the latest two cycles
Do not conclude: “32 billion is guaranteed.” Several chipmakers now report a doubling cadence closer to 2.5–3 years, not 2. The useful habit is projecting the trend and then checking it against the most recent real data, not treating the 2034 number as settled.
History & Accuracy

The “law” has a more precise origin than the folklore.

Expand for the distinction between what Gordon Moore actually wrote, what later got attached to his name, and where the trend stands today.

What did Gordon Moore actually say in 1965?

In an April 19, 1965 article in Electronics magazine, “Cramming more components onto integrated circuits,” Moore observed that the number of components per integrated circuit had been doubling every year and projected that pace would continue for at least a decade. In 1975, he revised the estimate to roughly doubling every two years. The name “Moore’s law” was coined and popularized by Caltech professor Carver Mead shortly after that 1975 revision, not by Moore himself.

Why do people also say “performance doubles every 18 months”?

That figure is commonly traced to David House, an Intel executive, who in 1975 reasoned that combining the doubling of transistor count with faster, more efficient transistors (via what is now called Dennard scaling) implied roughly an 18-month doubling in chip performance. Moore’s own claim was narrower: it was about transistor density, not performance. Moore later said he never stated an 18-month figure, and after Dennard scaling broke down in the mid-2000s, transistor-count growth stopped translating directly into proportional performance gains — which is a large part of why the industry shifted toward multicore chips and specialized accelerators.

Is Moore’s Law dead?

This is genuinely disputed rather than settled. Intel’s own leadership has revised the cadence over time (roughly 2.5 years per Brian Krzanich in 2015, closer to 3 years per Pat Gelsinger at the end of 2023), while Nvidia’s Jensen Huang publicly declared Moore’s Law “dead” in September 2022, a claim Gelsinger disputed soon after. The semiconductor industry’s own roadmap body issued its final “Moore’s Law”-framed roadmap in 2016 and shifted toward a “More than Moore” strategy, emphasizing application-specific chips, packaging and parallelism over raw transistor scaling. The honest summary: the original transistor-density trend has slowed and grown more expensive, even as overall computing capability keeps improving through other means.

Common Mistakes

A 60-year trend is still not a law of physics.

Treating it as a physical law

Moore’s Law is an empirical, economically driven observation about engineering and investment, not a law of nature. It can slow, stop or restart in a different form.

Confusing transistor count with speed

More transistors do not automatically mean proportionally faster chips, especially since Dennard scaling ended in the mid-2000s. Check which specific metric — density, clock speed, cost-per-computation — you actually depend on.

Assuming one person’s number is official

“Doubling every 18 months” (performance), “every 2 years” (Moore’s revised transistor estimate) and “every year” (Moore’s original 1965 estimate) are three different claims from different people. Be specific about which one you are relying on.

Extrapolating past the limit silently

Exponential curves that run into physical constraints (heat, leakage, materials) typically flatten into an S-curve. Projecting a straight exponential line indefinitely overstates what is coming.

Ignoring cost alongside capability

“Rock’s Law” observes that the cost of building a semiconductor fab has itself roughly doubled every four years. A trend can continue technically while becoming economically out of reach for all but a few companies.

Applying it outside computing without checking

Doubling-style trends show up in batteries, genomics and solar costs too, but each has its own cadence and its own limits. Borrowing the phrase “Moore’s Law for X” is only useful if the underlying data for X actually supports it.

When Not to Use It

Some resources were never on this curve.

Use direct measurement when...

you have only one or two data points. A doubling claim needs several comparable cycles before it is a trend rather than a coincidence.

Use S-curve thinking when...

the resource is a biological, social or physical system known to saturate — population, adoption, or anything bounded by a hard ceiling.

Use direct expert forecasts when...

domain specialists already track and publish the actual cadence (as chipmakers now do), rather than reasoning from the 1965 or 1975 figures in the abstract.

Counterpoint: the lesson people most often take from Moore’s Law — “exponential trends always continue” — is the opposite of what its own history shows. The trend held for decades, then slowed. Both halves are the lesson.
Combine It With

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Try It Yourself

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Save as Skill converts the model into portable Markdown instructions that teach an AI when and how to apply Moore’s Law, what questions to ask, what evidence to seek, what mistakes to avoid and how to structure its analysis.

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Go Deeper

For readers who want the nuance.

Is there a “second” Moore’s Law?

Yes — informally, “Moore’s Second Law” (also called Rock’s Law) observes that the capital cost of building a semiconductor fabrication plant roughly doubles every four years. Capability has kept scaling even as the cost of staying at the leading edge has made it an increasingly concentrated industry.

Does Moore’s Law apply to AI progress?

“Moore’s Law for AI” is a loose borrowing of the phrase, usually describing separate trends such as training-compute growth or cost-per-FLOP decline. These trends have their own drivers and are not the same claim Moore made about transistor density in 1965. Treat each one as its own empirical trend to verify, not as an extension of the original law.

What would make the trend restart or accelerate?

Historically, new transistor geometries (such as FinFET and later gate-all-around designs), new materials, and packaging innovations (such as chip stacking) have extended the trend past points where it looked like it would stall. A slowdown in one approach does not rule out a different engineering path picking up the pace again.