Alternative form of if it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck

(philosophy) A thought experiment, asking, "if a man born blind can feel the differences between shapes such as spheres and cubes, could he, if given the ability to see, distinguish those objects by sight alone, in reference to the tactile schemata he already possessed?"

A type of thought experiment in ethics and psychology, involving ethical dilemmas of whether to sacrifice one person to save a larger number.

(computing) The problem of how to create a superintelligent AI whose values would align with the interests of humankind.