In theological and philosophical language, "nature" simply means the set of attributes and characteristics that make an individual thing what it is. So when we talk about "human nature," we mean such characteristics as: descended from Adam, made in the image of God, bipedal, sexually dimorphic, capable of speech, capable of reason and abstract thought, and so forth.
The actual philosophical/theological/scientific discussion about this is more complicated, but this serves to point out that we're not really talking about a difficult concept. Having a
human nature is synonymous with being a
human being.
As pertains to the person of Christ, we also have the concept of the
hypostatic union: his divinity and humanity are united in a single, individual existence. The human and divine natures are distinct, but not divided: as the Definition of Chalcedon (AD 451) says, Christ is
recognized in two natures, without confusion, without change, without division, without separation; the distinction of natures being in no way annulled by the union, but rather the characteristics of each nature being preserved and coming together to form one person and subsistence.
In other words, we must not think of the hypostatic union as a divine spirit possessing a human body, or combining into some third kind of nature that is neither distinctly human nor divine. Full humanity and full divinity come together in the person of Jesus Christ. Every attempt to explain the hypostatic union has resulted in a heresy that either divides or confuses the two natures. Nonetheless, its fact remains true. It takes a leap of faith to accept it.
The true Christian position is termed
dyophysitism: two natures. This is in contrast with
monophysitism, the heretical belief that Jesus had only a single, divine nature. Related concepts are
mono- vs.
dyothelitism: the question of whether Christ possessed one will or two, one human and one divine. Monothelitism was rejected by the whole church in the seventh century. If Christ is both
fully human and fully divine, then he must possess both a human and a divine will, which is not to say the two natures/wills are ever in conflict.
When Vince says, for example:
Now, we are taught that Jesus had two natures, one human and one Divine. I took Systematic Theology at HAC, where the textbook presented arguments (both for and against) the doctrines that Jesus had one, two, or three natures. Unfortunately, the textbook convinced me that all three positions are wrong.
he is saying that the theological affirmation of Jesus' human and divine natures is in error. Revealed Scripture speaks of Jesus as a man, and as God. It does not literally speak of him possessing the essential characteristics of any other kind of being. Thus "the doctrines that Jesus had... two... natures" is in fact true. Vince defies the orthodox definition of the hypostatic union.
Several heresies, almost all monophysite, arose in the early church, that denied or distorted the human nature of Christ:
- There is Docetism. This is a full denial of Jesus' humanity that claims his human body and human existence were a mere appearance, having no reality. (One major implication of Docetism is that when Jesus appeared to the disciples after his resurrection, the wounds from the crucifixion that he showed Thomas to prove he had risen from the dead were an illusion. He tricked Thomas into confessing, "My lord and my God!")
- There is Apollinarianism. This was a novel teaching of Apollinarius, a late-fourth-century bishop of Laodicea. He affirmed that Jesus had a true human body and soul; however, he did not possess a human spirit, but was instead animated by the Spirit of God.
- There is Nestorianism. Nestorius was one of Apollinarius's opponents. He regarded birth as an essentially human activity, and therefore denied that Mary could in any sense be regarded as theotokos ("God-bearer")--a term that had come into being to affirm that Jesus Christ was divine even in the womb. Nestorius preferred terms like christotokos ("Christ-bearer") or anthropotokos ("man-bearer"). Hence he ended up denying the union of the two natures, believing Jesus was simply a perfect man linked to deity. It's unknown how much of Nestorianism reflects Nestorius's own beliefs, as opposed to the embellishments of his followers.
- I have observed a modern revival of Nestorianism amongst some fundamental Baptists. Like Nestorius, they don't like the idea of Mary as theotokos because it's too "Catholic." And so they swing too far in the opposite direction, claiming that Mary gave birth to Jesus' humanity but none of his divinity. Some of these people even go farther, claiming Mary was a mere "incubator" for Jesus' body. This too is heretical: like Docetism, it is a denial of Jesus' humanity. Not in the sense that his body was an illusion. But if Jesus is not truly the descendant of Mary, then though he may have had the appearance and biology of a man, he had no true connection to the human race.
- There is Eutychianism. Eutyches of Constantinople opposed Nestorius with an extreme opposite position: that the human and divine natures blended into something that was neither distinctly human nor divine. The divine nature consumed the human nature in such a way that Christ was of one substance (homoousion, a term that should be familiar from the Arian controversy) with the Father, but not homoousion with humanity.
By the time of the Council of Chalcedon in 451, the last ecumenical council considered authoritative by the consensus of all of Christendom, all these positions were soundly rejected by the church.
