The train of thought, or occasionally, chain of thought refers to the interconnection in the sequence of ideas expressed during a connected discourse or thought, as well as the sequence itself, especially in discussion of how this sequence leads from one idea to another. This construct relates the stringing together of ideas to the way train cars are connected on a track.
When a reader or listener "loses the train of thought" (i.e., loses the relation between consecutive sentences or phrases, or the relation between non-verbal concepts in an argument or presentation), comprehension is lost of the expressed or unexpressed thought.Edward Parmelee Morris, "On Principles and Methods in Latin Syntax" (1901), Chapter VI: Parataxis
Origins The term "train of thoughts" was introduced and elaborated as early as in 1651 by Thomas Hobbes in his Leviathan, though with a somewhat different meaning (similar to the meaning used by the British associationists):
See also
Absent-mindedness Association of Ideas Associationism Derailment (thought disorder) Internal monologue Mind-wandering Stream of consciousness
References