With a background in applied mathematics, Prof. Donald MacKenzie has recently been named among the top twenty-five brains of the financial crisis. He is also a pioneer in developing the discipline of social studies of finance. For decades, he has explored new fields in the sociology of science and technology, especially those that deeply affect people's lives, such as the eugenics movement, the accuracy of nuclear weapons, emissions markets, and his recent work on current credit crunch. This interview started with a simple but baffling question: how could it be possible that one plus one does not always equal two? We then attempted to find a thread from a diversity of his research topics. He responded that most of his studies revolve around the application of mathematics and its impacts on our daily lives. We also asked for his comments on the Bloor-Latour debate. To this request, he replied with what he described as a “very biased Edinburgh School answer”: he sees the attacks on the Edinburgh School as attacks on a sociologically reductionist misunderstanding of its position. At the end of this interview, he encouraged East Asian scholars to move away from the traditional topics and to be prepared to search for novel ones.