One of the precursors to this type of programming was Church (http://projects.csail.mit.edu/church/wiki/Church http://projects.csail.mit.edu/church/wiki/Church)

One of the precursors to this type of programming was Church (http://projects.csail.mit.edu/church/wiki/Church http://projects.csail.mit.edu/church/wiki/Church), a Scheme-based probabilistic programming language. I guess they're separating from said Church? :)