That unique willfulness of man is the non-corporeal, non-spatial, non-temporal - spirit or soul.
If there is a plurality of souls, each being "non-corporeal, non-spatial, non-temporal", how would one soul be distinguished from another?
This field-like willfulness which is associated with life everywhere - whether an individual amoeba, bacteria, swarm of bees, whale, man, etc. - is manifest first and foremost as a will to live, a want to live or a struggle to survive. It appears in creatures with brains, without brains and also in collectives of creatures - like ants and bees. In Scripture, Genesis 1, this is called the nephesh. The collective, the whole of physical creation, is also spoken of in Romans 8 as a "one" with willfulness. This is what may be considered a "collective consciousness".
But man is particularly willful - individually willful. He has a sense of good and evil, right and wrong, altruism and selfishness. He makes peace and war, choices for good or ill. He is uniquely and individually self aware as compared to the nephesh of all life, though he is certainly also that - having a will to live.
In Scripture, this is called a ruach. Each of us has this sense of good and evil.
And then there are certain men (not all) who have a sense of transcendence, of belonging to something much greater, beyond space/time. In Scripture parlance this would be called "ears to hear". In Genesis 2, it is called neshama - the breath of God and is unique to Adamic man - the spiritual descendants of Adam.
A man who has the neshama also has the ruach and the nephesh. It is a gradient of who he individually chooses to be.
But there is more. In addition to all of this a Christian man receives the indwelling of the Spirit of God. He becomes a new person, abiding "in" the beyond which he only previously sensed. I do not know a Hebrew word for this, however the Scriptual references include John 3, 15-20, Romans 8, I Cor 2.
To sum it all up, the individual man is an individual - a unique status among all other life. His self-will so far exceeds the "will to live" of ordinary life, that we must look beyond space/time, beyond the corporeal, to understand how it came to be.