Edwards splits necessity into two categories: natural and moral. Natural necessity relates to our actions, moral necessity relates to our wills. If an act is naturally necessary, it is either against or without our will, and whether we will or not the result is the same. Edwards says that natural necessity is the common meaning of necessity and moral necessity is philosophical. Natural necessity (common necessity) is a sense wholly different than that used in the Calvinist/Arminian debate. Most people go through their whole lives without thinking about moral necessity (philosophical necessity) and its relationship with responsibility.
People use the terms “must, cannot, necessary, unable, impossible, unavoidable, and irresistible” signifying natural necessity. Natural necessity is incompatible with responsibility. The common notion of responsibility is A) doing what we please and B) what we please being wrong.
Arminians equivocate common and philosophical necessity. People don’t notice when they move the inconsistency of necessity from the actions of our body (common necessity) to the actions of our wills (philosophical). Thus, they mistakenly conclude that the actions of our wills must be free, based on the common sense notion that the actions of our bodies must be free.
The division between natural and moral necessity into two alternative senses is invalid. What we have is one sense for necessity applied within two different contexts. X is necessary if the opposite is impossible. X can either be actions of our bodies or actions of our wills.
When we ask if choices are necessary or free, we are not using a new sense for the term necessary. It’s the same term people use in every day conversation.1 Are we able to choose X? Thus we are not equivocating.
An odd consequence of Edwards view is that many of his interpretations of Scripture end up being philosophical. The ideas of irresistible grace, total depravity and even God’s commands applying directly to acts of the will, end up in the “philosophical necessity” category that Edwards says most people don’t think of throughout their whole lives.
1In philosophical discussions we do distinguish between causal, accidental, logical and joint-logical necessity, but these categories relate to the source of necessity, not the type of necessity. But these distinctions are not required to understand LFW, even if they may be required to discuss some exotic topics.