We are influenced in our choices by many factors, we can be mistaken and free will can be defeated by, for example, hypnosis. Nevertheless we have the ability to choose: we have causal origination.
The idea that free will is illusory derives from a simplistic view of the universe. It is reasoned that consciousness arises from the brain and the brain is part of the universe and so therefore can only display deterministic or random behaviour. This view is reinforced by a mistaken view of the brain as some sort of computer. We agree that if the brain were a computer then it would have no possibility of free will: any "choices" it made would be determined by the input to and state of the program.
Against this, we point out that consciousness has yet to be explained and that physics is incomplete. The question of free will is therefore open. This camp believes that a realistic understanding of causality, consciousness and the brain will confirm the reality of agency.
There is evidence from experiments performed by Libet and others that appears to show that the unconscious brain decides for us. We are not convinced and note that there is contrary evidence such as Trevena and Miller.