Early social contract theorists argued that human beings were free and rational actors who willingly entered into a social contract. The application of their ideas to the criminal justice system formed the basis for the classical school of criminology. Within this approach, barbarous and cruel punishments were viewed as unnecessary; emphasis was placed on punishment that was swift, certain, and fitting to the crime. While this approach remedied excesses of the old regime, it resulted in a rigid and inflexible criminal justice system and many new injustices. This led to a series of neoclassical reforms that provided the basis of the modern system. The emergence of the positive school marked the beginning of the modern era. These theorists insisted that scientific methods replace the philosophical approach of the classical schools. Work by Lombroso and his colleagues shifted the emphasis away from individual responsibility to a conception of the criminal as a defective person who needs to be treated rather than punished. 7 annotated references. (Author summary modified)