Within the free will debate, libertarianism denotes freedom in the metaphysical sense and not in the political sense. A libertarian believes that actions are free—that is, not caused by external forces. We are free to plot our course through our actions. Existentialists further argue that our essence is the product of our choices.
Many proponents of the libertarian view assume the definition of freedom inherent to the Principle of Alternative Possibilities (PAP). We are free if and only if we could have done otherwise at a specific time.
There are many challenges to this assertion. One objection, based on Benjamin Libet’s neuroscience-based experiments, suggest that many of the actions we perceive as free are, in fact, caused and determined by the brain.
Video
The Libet Experiment: Is Free Will Just an Illusion?
This video, from the BBC Radio 4 series A History of Ideas, is narrated by Harry Shearer and scripted by Nigel Warburton.
The content of this course has been taken from the free Philosophy textbook by Openstax