If God is omnibenevolent and omnipotent could not we say God is capable of giving us free will without the existence of evil based on the same logic as Descartes described God's ability to lift an unliftable rock?
Alvin Plantinga has argued that even an omnipotent God might not be able to create a world in which free creatures always 'go right', and never morally wrong ('evil') in their chosen actions.
Free will and no evil
J.L. Mackie argued in line with your question :
that 'God is omnipotent, omniscient and perfectly good' entails 'Any free creature created by God would always "go right" with respect to freely chosen action. J.L. Mackie, 'Evil and Omnipotence', Mind, Mind, Vol. 64, No. 254 (Apr., 1955), pp. 200-212: 209. (Summary of Mackie's view : Nelson Pike, 'Plantinga on Free Will and Evil', Religious Studies, Vol. 15, No. 4 (Dec., 1979), pp. 449-473: 449.)
Free will and necessary evil
Plantinga produces a counter-argument :
- God is omnipotent, omniscient and perfectly good.
- It is not within God's power to create a world containing free creatures who perform morally right actions but who do not (also) perform some morally wrong actions.
- God created a world containing free creatures who perform morally right actions.
- Therefore God created a world containing free creatures who (also) perform some morally wrong actions.
Plantinga claims that the conjunction of lines I-3 is 'evidently consistent'. At first it might seem that lines I and 2 are in logical conflict since 2 appears to be inconsistent with the idea that God is omnipotent. However, Plantinga has argued that since it is possible that every creaturely essence has transworld depravity, it is at least possible that not even an omnipotent being could create a world containing free creatures who perform right actions without creating a world in which these same creatures sometimes do what is wrong. It is thus possible that line 2 is true even though God is omnipotent. Observe, lastly, that the conjunction of lines I-3 entails 4. The conclusion is that Mackie is wrong: lines I and 4 are logically compatible. As a general principle, a proposition P (in this case I) and a proposition Q (in this case 4) are jointly consistent if there exists a proposition R (in this case the con junction of lines 2 and 3) which is such that P and R are jointly consistent and jointly entail Q. (Nelson Pike, 'Plantinga on Free Will and Evil', Religious Studies, Vol. 15, No. 4 (Dec., 1979), pp. 449-473: 454.)
Critique of Plantinga
Pike offers an elaborate discussion of Plantinga's argument. Regardless of his final position it is worth noting a prima facie strong objection he presses against Plantinga:
Assume for the moment that although God is omnipotent, it is not within his power to create a world containing free creatures who perform right actions but who do not also perform some actions that are wrong. Is it clear that under these circumstances, a perfectly good being would create a world containing free creatures who do what is right? If he could not create the latter without creating a world in which creatures sometimes do what is wrong, perhaps the right conclusion is that a perfectly good being would create no world at all or would create a world containing no free creatures and thus one containing no morally significant actions, right or wrong. Note that if this were the right conclusion, then although we might grant the compatibility of lines 1 and 2 in the above array, the conjunction of lines I-3 would not be consistent. The negative consequences for Plantinga's programme would be nothing short of decisive. (Pike : 454.)
Defence of Plantinga
Pike thinks this objection can be overcome. In sum he argues, siding with St Augustine :
On Augustine's view, a perfectly good being might create free creatures whom he knows in advance will perform morally wrong actions even if he could as readily create only creatures whom he knows in advance will always do what is right ... It just depends on which free creatures will contribute most to the ultimate good. Of course, we are not in a position to know which free creatures these might be. (Pike: 473.)
It depends on what one means by evil. The definition of evil tends to depend on the subjective outlook on the world of any given person, or a collection of some accepted definition by a group of people, such as culture and laws. Perhaps it is possible if there is a universal definition of what is considered evil, then god is capable of providing free will without evilness by limiting us to certain behaviors contradictory to the definition of evil; or perhaps evilness is reduced to some idea of being what is unfavorable to us, subjective and thus dependent on the individual, then such a task has already been accomplished with or without the existence of god.
For what action is good when there is nothing morally different from it? Goodness seems to exist because of evilness.
This may be off topic, but if god is such an entity with choice, it is not a matter of whether this entity has the power to give us free will without evil, but if such an entity actually wants to.