From Roger E. Olson's Arminian Theology. See also Myth #1.
Myth #2: A hybrid of Calvinism and Arminianism is possible.
Truth: In spite of common ground, Calvinism and Arminianism are incommensurable systems of Christian theology; on issues crucial to both there is no stable middle ground between them.
The gap between the two has to do with the 3 middle points of the TULIP scheme:
Perseverance of the saints
Classical Arminianism ...
--teaches total depravity.
--teaches conditional election.
--teaches Christ’s atonement was universal in scope. It’s for everyone who believes.
--teaches grace is necessary for salvation, and prevenient grace is given to all men to free their will to chose for or against Christ; but that grace is not irresistible according to God’s own design.
--teaches the perseverance of the saints who persevere in faith.
Both Calvinists and Arminians believe that God is great and good.
Calvinists start with God’s greatness. Thus do they find it difficult that man would have any say in his salvation, even to say “yes” or “no” to the gift. For that, they say, diminishes God’s greatness.
Arminians start with God’s goodness. Thus do they find it difficult that God would choose that some would not be saved and go to hell for an eternity of suffering.
Not only that, but if God is sovereign in such a way so that man has no free will, then all sinful acts have been ultimately caused by God, and man cannot be held responsible.