The new science of probability and statistics was mainly used in astronomy at the time, where it was essential to account for measurement errors around means. This was done using the method of least squares. Quetelet was among the first to apply statistics to social science, planning what he called "social physics". He was keenly aware of the overwhelming complexity of social phenomena, and the many variables that needed measurement. His goal was to understand the statistical laws underlying such phenomena as crime rates, marriage rates or suicide rates. He wanted to explain the values of these variables by other social factors. These ideas were rather controversial among other scientists at the time who held that it contradicted the concept of freedom of choice.