If you wanted an argument in early Christendom the issue of the Incarnation would always serve. Truly man or just pretend? Truly God or just inspired? Two persons with two natures or one person with two natures? Two wills or one will? Eventually, of course, we emerged with one person with two natures and so with two wills. Unfortunately orthodoxy still leaves us with mystery, and plenty of room left for debate.
One problem concerns knowledge. Christ was omniscient in his divine nature. How does this fit with his human nature? His human knowledge was processed through his human brain, and so it must have developed according to the stages of brain development. There was no danger of his sitting up in his manger and delivering a brief explanation of quantum mechanics. All he knew was the warmth of his mother’s breast and the smell of milk. But by the age of twelve he knew enough to quiz the elders in the Temple in his pursuit of his Father’s business, and his wisdom was to increase thereafter. Even the proclamation of his Father’s revelations cannot, as such, exceed the capacity of his or our human brain. “He who has seen me has seen the Father” – perhaps the deepest metaphor ever presented to mankind – remains a metaphor.
It wasn’t until the 7th century that the idea that Christ might have only one will was scotched. It puzzles our shallow minds that he had two wills, one human and one divine. Our everyday experience leads us to conflate “person” and “nature” but, as the Incarnation reminds us, these concepts are essentially different. In fact Christ’s human will harmonised with the divine will, without losing the limitation of being human.
And perhaps there’s the rub. Homo sapiens is not born as a blank sheet. He is, to use a modern metaphor, programmed. We need, for instance, to have no doubt that his mother and father’s upbringing helped to shape his adult life. And, through his relationship with them he learnt about the male and female character, and the bonding of two persons in marriage. Nor need we suppose that he was a goody two shoes; it is natural for the young to learn through parental correction. But human programming has a much longer history than that. It started in a primitive form of life and evolved through billions of evolutionary steps to a stage fit to receive the characteristics of intelligence and free will. You, I and Christ are cousins of the jellyfish, albeit rather far removed.
Instincts and emotions provide useful examples because we have inherited many of these from the lower animals. Our instinct to react immediately, both emotionally and physically, to signs of danger comes from our animal past. Our openness to altruism can readily be explained by its rôle in assisting the survival of pre-human groups. The hormone oxytocin, valuable in the bonding of intimate relationships — from the care of the whining baby to the physical love of marriage, is also present in dogs who love their humans. Perhaps the most prominent of our inherited instincts is that of reproduction, as any documentary recording the life cycle of a species will show. To which we must add the workings of the brain through which by far the largest portion of our mental activity is processed without our conscious attention. Its 22 billion neurons have been programmed through evolution and experience for a great range of tasks which we do not yet fully understand.
Christ, the man, was subject to all of this for his human nature was a fallen one, vulnerable to fear, sorrow and pain, and, on the cross, even vulnerable to that sense of abandonment which God reserves for very special souls. He is subject to sinful temptations including those resulting from the extensive passions of our lower nature, which, of course, he shares. Here we distinguish three stages: initial (unchosen) stimulus, contemplating the temptation, surrendering to the temptation. Christ only experienced the unbidden stimulus, then, through his human will, actively attuned to his divine will, rejected the further stages.
There is a danger that our grasp of Christ’s human nature is only notional. We have to face up to the fact that he was really one of us, experiencing humanity in all its knobbly, natural aspects, just as we do. It is precisely because we all share humanity that the redemption of human nature, through his suffering, could come about. And, as Hebrews emphasises, it is through this sharing that he can sympathise with our weakness because he has been tested in every respect as we are, and yet remains without sin. We recognise Christ in many ways, but we should never forget that he led us on the battlefield as a true comrade in arms.