**Links to**: [[Chunk]], [[Parse]], [[Rationality]], [[Reason]], [[Intelligence]], [[Pattern]], [[Linearity]], [[Scale]], [[Concept]], [[Inference]], [[Thought]], [[Legitimacy]], [[Authority]], [[Dialogical]], [[Private-public]], [[Collective intentionality]], [[Sense]], [[Deduction]], [[Induction]], [[Abduction]], [[Semantic attractor]], [[Philosophy]], [[Intuition]], [[Cognition]], [[Logic]], [[Invention]], [[Real abstraction]], [[Real and imaginary]], [[Revealed or rational]], [[Active inference]], [[08 Active ignorance]], etc. >Every description of events in space involves the use of a rigid body to which such events have to be referred. The resulting relationship takes for granted that the laws of Euclidean geometry hold for “distances,” The “distance” being represented physically by means of the convention of two marks on a rigid body. Einstein, Special Theory of Relativity, p. 9. This citation also appears in [[Linearity]]: >The practice, for example, of seeing in a “distance” two marked positions on a particularly rigid body is something which is lodged deeply in our habit of thought. We are further accustomed further to regard three points as being situated on a straight line, if their apparent positions can be made to coincide for observation with one eye, under suitable choice of our place of observation. Einstein, Special Theory of Relativity, p. 5.