Is there a word or phrase that describes the following condition?
Once you have an idea, you are incapable of letting go of it until you have explored every conceivable branch from the idea and reached all possible logical conclusions.
Inspired by terminology from risk analysis and decision science as well as the language and framework of Myers–Briggs Type Indicator (MBTI) cognitive styles
indeed, INTJs can hardly rest until they have things settled, decided, and set. They are the people who are able to formulate coherent and comprehensive contingency plans, hence contingency organizers
the following phrases capture the anticipatory and closure-driven aspects of the trait that you are describing:
- exhaustive contingency reasoning style/preference/pattern
- scenario-tree cognitive style/preference/pattern.
To actually characterise the trait as a condition, you could instead call it
A related term, from psychology, is "monotropism", which is neither as precise nor particularly accurate to the OP's specific description:
Monotropism is an individual's tendency to focus their attention on a small or singular number of interests at any time, with them neglecting or not perceiving lesser interests.
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A tendency to focus attention tightly has a number of psychological implications, with it being seen as a state of "tunnel vision".
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this form of hyperfocus makes it harder to redirect attention
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Finally, I think that the commenter-suggested "idée fixe" (literally, "fixed idea") crucially fails to capture the OP's stated criterion, namely generative rumination—specifically, one that cascades and branches exhaustively. Besides, this suggestion is even more loaded than the final bullet above.
Tangential; too long as a comment
I found a lot of ancillary utility in reading your answer. Particularly amusing to me was the fact that MBTI is considered psuedoscientific, yet the profile description above summarises my personality traits to a tee.
Thanks for the kind note. MBTI classifies normative cognitive/learning preferences by how individuals are most naturally inclined to engage with information (pattern-oriented vs. concrete; outward-focused vs. inward-focused) and make decisions (values-based vs. logic-based; structured vs. holistic); specifically, the interaction of these two two-dimensional factors yields 16 non-uniformly distributed cognitive patterns.
Outside the physical sciences, scientific rigour exists on a spectrum; wherever MBTI ultimately sits, the charges of pseudoscience are understandable. The framework's four dichotomies are unfortunately named ("Introversion-Extraversion", "Sensing-Intuition", "Thinking-Feeling", "Judging-Perceiving"), and its four-letter labelling system perpetuates two key misunderstandings that contribute to an impression of reductive caging: that the four dichotomies are unrelated dimensions rather than functionally interlocked, and that the model implies that cognitive tendencies have invariant expressions across contexts and regardless of ongoing developmental change.