“On molinism, is it possible that Adam could have not sinned? If so, then there is a world where Adam was righteous but God didn’t actuate it. If not, then there is no world in which Adam was never able to not sin, and yet God actuated that world.
So, did God knowingly actuate a world where Adam would fall?”
This is a fantastic question, Anthony! It is so important for the Church to understand these deep issues regarding Molinism. This is the case because when the Church clearly understands that humans are responsible for sin and evil (as opposed to God determining humans to think and act sinfully) then we can impact the skeptical culture we live in with reasonable answers to the so-called “problem of evil.” Let me respond to your inquiry one step at a time.
//On molinism, is it possible that Adam could have not sinned?//
Yes! The Molinist would affirm that there is a logically possible world in which Adam does not ever sin; however, this might not be a feasible world for God to actualize (we are not in an epistemic position to know, but God would know with omniscient certainty). There is a vital difference between logically possible and feasible worlds.
//If so, then there is a world where Adam was righteous but God didn’t actuate it.//
Since it is logically possible that Adam never sinned, just as it is logically possible that you will never sin again (there is no logical contradiction with the proposition), then there is a possible world in which Adam never sins. However, it could be the case that in every world in which God creates Adam with libertarian free will (LFW), Adam always freely chooses to sin. Thus, it would be impossible for God to create the logically possible world in which Adam never freely chooses to sin. This world is known as a possible world which is non-feasible to actualize. That is to say, this world is not a feasible world.
Now, God has the power to create a world in which He causally determines all of Adam’s thoughts, actions, beliefs, and behaviors. Thus, there is a logically possible world in which Adam never makes any genuine choices — including sinful choices — at all, but that would also include Adam’s inability to make a genuine choice to follow, trust, and love God. This is a world in which Adam does not possess LFW, and thus, does not choose to love God.
//If not, then there is no world in which Adam was never able to not sin, and yet God actuated that world.//
If Adam is genuinely “able” (as you said), then a possible world exists in which Adam never sins. However, as I noted, if Adam always freely chooses to sin in every world in which he possesses LFW, then God could not actualize a world in which Adam always freely refrains from sin (never sins). This brings us to your final question:
//So did God knowingly actuate a world where Adam would fall?//
Yes! God created a world in which He knew that Adam would freely choose to sin. Thus, Adam did not have to sin (knowledge does not stand in causal relation) and he was respons-ABLE. Yet, God, by creating this world, still elected and predestined Adam’s sin, although He did not causally determine Adam to sin (that was up to Adam).
It is vital to understand the philosophical difference between predestination and causal determinism. Many pastors, Sunday school teachers, and churchgoers in general conflate these two different concepts. This leads to erroneous and imperfect thinking about the nature and character of our perfect God.
Stay reasonable (Philippians 4:5),