Definition
Ask ten experts what AI is and you may get ten answers. They're all looking at the same elephant from different sides.
There's no single agreed definition of AI. The main ones fall along two questions: is the goal to think or to act, and should the standard be human behaviour or rational behaviour? Russell and Norvig's textbook, the standard reference, defines AI as the study of agents that act rationally.
In simple words
One group says AI should copy how people think. Another says just make it behave like a person from the outside. A third says forget people, make it reason correctly. The fourth, which most engineers follow today, says it should simply take the best action available to reach its goal.
Why it matters
Definitions decide what gets built, what counts as success and what the law covers. If someone claims their product is AI, or that AI has reached human level, you can ask: by which definition?
How it works
The four approaches (Russell & Norvig)
| Human standard | Rational standard | |
|---|---|---|
| Thinking | Think like humans: model how people think (cognitive science). | Think rationally: follow correct logic. |
| Acting | Act like humans: pass as a person (the Turing Test). | Act rationally: take the best action for the goal. This is the modern view. |
Definitions from the founders and regulators
| Who | Definition | Focus |
|---|---|---|
| Alan Turing, 1950 | If a machine can pass as human in conversation, we should grant that it thinks. | Behaviour |
| John McCarthy, 1955 | The science and engineering of making intelligent machines. | Engineering |
| Marvin Minsky | Making machines do things that would require intelligence if done by people. | Tasks |
| EU AI Act, 2024 | A machine-based system that infers from its input how to produce outputs such as predictions, content, recommendations or decisions. | Law |
| OECD, 2023 | Close to the EU wording. Systems vary in how autonomous and adaptive they are. | Policy |
Try it yourself
Four ways to define AI
The experts asked different questions, so they got different definitions. Travel through them.
Who said it?
Match each idea about AI to the person or book it comes from.
- "Can machines think?" Let's test it with an imitation game.
- AI is "the science and engineering of making intelligent machines".
- AI is making machines do things that would need intelligence if people did them.
- AI is the study of agents that sense their environment and act to do the best they can.
The four ways of looking at AI
Textbooks group definitions into four views. Put each goal in the right view.
Chat so well that people can't tell it's a machine
Copy the way people solve puzzles, mistakes included
Reach only conclusions that follow by strict logic
A delivery robot choosing the fastest safe route
Common mistakes
- Thinking only one definition is right. They answer different questions.
- Treating passing the Turing Test as proof of real understanding. It tests behaviour only.
Check yourself
Summary
- There's no single definition of AI.
- Four approaches: think or act, like humans or rationally.
- Engineers and textbooks mostly use the rational-agent definition, and laws use the broad system definition.
Finished reading?
Sources: Russell & Norvig, Artificial Intelligence: A Modern Approach · EU AI Act, Article 3