The art of thinking · First principles thinking and its adaptations
First-principles calculation
Also known as: Ab initio calculation, Ab initio method, First-principles method
In physics, chemistry and materials science, a first-principles (ab initio) calculation predicts properties of atoms, molecules or materials directly from the fundamental laws of physics — in practice quantum mechanics — without parameters fitted to experimental data for the system being studied.
- Thinking models
- Engineering
- Physics
In one sentence
A first-principles (ab initio) calculation predicts properties of molecules or materials from quantum mechanics without fitted experimental parameters.
Example
Before a new battery cathode material is synthesized, density functional theory calculations estimate its voltage and stability from the arrangement of its atoms.
Explained in context
Context cards connect this term with others to answer one question. Also in British English and German.
How it applies
- Science and engineering: Ab initio methods of quantum chemistry and density functional theory are used to study materials, catalysts, semiconductors and batteries before they are made. Walter Kohn (density functional theory) and John A. Pople (computational methods in quantum chemistry) received the 1998 Nobel Prize in Chemistry for this work.
- Approximations remain: "From first principles" does not mean free of choices. Density functional theory, for example, depends on an approximate exchange-correlation functional. The method starts from fundamental laws, but its results still rest on model decisions that have to be stated.
- Meaning for first principles thinking: When engineers speak of reasoning "from first principles", they usually mean this scientific sense — starting from physical laws, not from earlier designs. The popular method of first principles thinking borrows the term from here.
How to read this pool
Entries, context cards and transitional topics
The art of thinking explains ways of thinking — where a method comes from, what it asks of you and how it was adapted later. You meet four kinds of content here, each with its own job:
- Glossary entry
- Defines one concept or method of thinking: its origin, an example and how it relates to neighboring ideas. “X vs. Y” sections set two methods side by side.
- Context card of the art of thinking
- A short, self-contained answer to one question about a way of thinking — its lineage, its steps, its limits. These cards are listed on The art of thinking only.
- Transitional topicBridges both pools
- A context card that bridges both pools: it shows how a way of thinking was adapted into documentation, analysis or quality practice. It sits with the reference context cards and is marked as transitional wherever it appears.
- Reference entry or context card
- Belongs to the Glossary & Norms Space on regulation, norms and engineering. Entries here link to one only where a method is also an established tool of documentation or quality work, such as the five whys or a user’s mental model.