Induction and deduction may be familkiar to most readers, but abduction may be a mystery. Essentially, it is a form of inference to the best explanation: you see a phenomenon of some sort and make a 'best guess' about what might explain that phenomenon. When Robinson Crusoe saw a pair of footprints and concluded there must be someone else on the island, he was inferring to the best explanation. Abduction is, as this post makes clear, a form of pattern recognition. Patterns are "reusable, structured, or formalised ways of doing things or processing information and data," or as defined by Alexander, "a three-part rule, which expresses a relation between a certain context, a problem, and a solution." Of course, patterns can be much mroe than that: "conceptual, iterative, representational, logical, mathematical, etc." The post concludes with some basic thoughts on computational pattern-detection.