IEEE Spectrum has a special feature on The Singularity. There is not one concise definition of this concept but the list of scenarios presented in the article Signs of the Singularity seems to do as good a job as any.
- The AI Scenario: We create superhuman artificial intelligence (AI) in computers.
- The IA Scenario: We enhance human intelligence through human-to-computer interfaces—that is, we achieve intelligence amplification (IA).
- The Biomedical Scenario: We directly increase our intelligence by improving the neurological operation of our brains.
- The Internet Scenario: Humanity, its networks, computers, and databases become sufficiently effective to be considered a superhuman being.
- The Digital Gaia Scenario: The network of embedded microprocessors becomes sufficiently effective to be considered a superhuman being.