Is self-will the same as the human spirit? To make you understand this, think about this situation: Adam and Eve sinned against God. Were they possessed by the spirit of the devil which hypnotised them and caused them to sin? Or were they posseseed by the Spirit of God? Or was it just self-will (and neither the spirit of the devil or of God) that made them sin...or was it just their own spirit controlling them? If this is the case, 'self-will', is self-will same as human spirit?
I think Paul helps us to understand, that what makes up our "will" is hidden from us in a way? That the Word of God must judge the thoughts and intentions of the heart, so that we can know and understand the "will" of God.
Ro 7:15 For that which I do I allow not: for what I would, that do I not; but what I hate, that do I.
16 If then I do that which I would not, I consent unto the law that it is good.
17 Now then it is no more I that do it, but sin that dwelleth in me.
18 For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not.
19 For the good that I would I do not: but the evil which I would not, that I do.
20 Now if I do that I would not, it is no more I that do it, but sin that dwelleth in me.
21 I find then a law, that, when I would do good, evil is present with me.
So I think it is clear that many of us would never sin again, if our "will" was the controlling factor of our lives, but there is another "will" a "law of sin" in us, and only when we die to self-will can we crucify this sinful part of us. Thus Paul teaches that all godliness, righteousness, holiness is a product of Gods Spirit working in and through us "to will and act according to Gods good pleasure"