Leeson,
Most of us (but not all) are "certain" that people have free will, though what exactly this amounts to is much less certain.
You are lawyer, so, how would you defend your position if I state that there is no free will because:
1.Person acts with free will only if he/she is the originator (or ultimate source) of her/his actions.
2.If natural laws are valid, and also cause/consequence (causality) is true, then everything any agent does is ultimately caused by events and circumstances outside his/her control.
3.If everything a person does is ultimately caused by events and circumstances beyond his/her control, then the agent is not the originator (or ultimate source) of her/his actions.
Therefore, if causality is true, then no agent is the originator (or ultimate source) of his/her actions.
Therefore, if causality is true, no agent, or person, has free will.
How would you explain free will?