[ima_banana]

This may be a dumb question, but is there a field of study of unintended consequences?

[seltzered_]

Complexity Theory / Santa Fe Institute folks might be in this domain. Jordan Hall recommends this book for starters: https://mitpress.mit.edu/books/thousand-years-nonlinear-hist...

[baddox]

Game theory is concerned with what will happen in interactions between actors with certain strategies and goals, so unintended consequences tends to come up a lot.

Public choice theory and social choice theory are related disciplines which concern themselves with the outcomes of various political and social mechanisms for making collective decisions based on individuals preferences and behaviors.

[beamatronic]

In many cases, that's economics.

[Frost1x]

I would say emergence and emergentism come to mind which captures many of these sort of ideas: https://en.m.wikipedia.org/wiki/Emergence

Oh and systems theory also comes to mind for more rigorous attempts at study: https://en.m.wikipedia.org/wiki/Systems_theory

[staticautomatic]

Closest I can think of is failure mode analysis.