Beginning in the 1950s, Chargaff became increasingly outspoken about the failure of the field of molecular biology, claiming that molecular biology was "running riot and doing things that can never be justified". He believed that human knowledge will always be limited in relation to the complexity of the natural world, and that it is simply dangerous when humans believe that the world is a machine, even assuming that humans can have full knowledge of its workings. He also believed that in a world that functions as a complex system of interdependency and interconnectedness, genetic engineering of life will inevitably have unforeseen consequences.