What's a "compatibilist"?
It's why Calvinists and Non Calvinists bump heads over defining freedom. Most of us Non Calvinists that believe in free will believe in 'libertarian' freedom which in a nut shell is the ability to choose between A and B or to not choose A or B, and to be able to do so without any compulsion against our will. To borrow Jerry Wall's definition:
"A free action is not one that is determined by prior causes or conditions. As he makes the choice, the agent has the power to choose A, and the power to choose not A, and it is up to him how he will choose".
Compatibilism ( or "soft determinism) is the Calvinist attempt to harmonize free will with moral responsibility. As Matt Slick defines it at CARM:
"Free will is affected by human nature but person cannot choose contrary to the fallen nature and desires. "Logically, someone could not make a choice contrary to his own nature. Furthermore, a person cannot make a choice if a person is not aware of the options. First of all, a person must be made aware of the concept or idea before a choice can be made. However, the Scriptures do declare that the unbeliever is a slave of sin and cannot receive spiritual things. Therefore, compatibilist free will is the biblical position."
Jerry Walls breaks down compatibilism as follows:
*A free act is not caused or compelled by anything external to the agent who performs it.
*It is, however, caused by something internal to the agent, namely, a psychological state of affairs such as belief, desire or some combination of these 2. It is something external that causes those internal beliefs and desires but the beliefs and desires actually belong to the agent, not the external cause of the desires and beliefs.
*The agent performing that action could have done differently if he had wanted to.