A fundamental issue in psychology is the issue of how much our behaviour can be attributed to choose, and how much to genetic programming. The natural sciences in general are based upon a deterministic approach to organic behaviour.
This approach implies that behaviour occurs in a regular and orderly manner which is predictable in principle and governed by our genetic makeup and disposition.
Because psychology is a relatively young science, it has relied upon imitating the basic principles of other sciences in its approach to human behaviour. Its application of the deterministic approach, however, has proved to be most controversial.
If people’s behaviour is genetically determined, how can they have free will? Furthermore, how can they be held responsible for their actions?
Most of the approaches discussed in mental health adhere quite firmly to a deterministic approach. However, humanist psychologists argue that people’s subjective experience of choice, free will and self-determination cannot be ignored, and is what makes us essentially human.
The question of free will is not just philosophical, for it raises the question of whether a science of human behaviour is really possible. If human behaviour is not governed by constant, predictable and provable factors, can it be effectively studied through experimentation and observation?