The philosophy of biology emerged as an independent branch of the philosophy of science under the influence of a handful of academic philosophers, mostly from North America, in the 1970s. This opened the door to an international exchange of ideas in the more speculative and controversial aspects of biology. Of special interest has been the relation between the ‘hard’ sciences of mathematics, physics, and chemistry, the ‘soft’ biological sciences, and the ‘even softer’ social sciences, also problems in the philosophy of mind and evolutionary theory.