Artificial intelligence system is able to finish tasks that are related to human cognitive functions,
for example, interpreting speech, patterns identifying, and playing games.
AI consistently learn how to do so by processing huge amounts of data, and searching for elements to affect their decision-making.
Sometimes an AI’s learning process is being directed by human forces, supporting good decisions and dismissing bad ones.
But some AI systems are directed to learn by themselves,
for example to keep repeating a video game more and more until the AI system finally understands the rules and how it works.

There is a strong AI system and a weak AI system:

A strong AI system is a system that can find solutions for problems that have never learned how to deal with same as human does.

A weak AI system deals with limited situations and is a simulation of human intelligence applied to a specific problem.
Examples of weak AI systems: are Siri, Alexa, Self-driving cars, and conversational bots.