  Quantitative social science is not only about regression analysis or, in
general, data inference. Computer simulations of social mechanisms have a
60-year long history. They have been used for many different purposes -- to
test scenarios, test the consistency of descriptive theories (proof-of-concept
models), explore emergent phenomena, forecast, etc. In this essay, we sketch
these historical developments, the role of mechanistic models in the social
sciences, and the influences from the natural and formal sciences. We argue
that mechanistic computational models form a common ground for social and
natural sciences and look forward to possible future information flow across
the social-natural divide.
