Someone told me recently that he didn’t understand how Jesus could have two natures. He wasn’t saying merely that he didn’t believe it, but that he found it incomprehensible.
One thing we need to guard against is the idea that things which are hard to imagine are hard to understand. Imagining and understanding are different things. One or the other may be hard in a given instance, but the one being hard doesn’t have to make the other hard. Examples may be multiplied of things which are easy to imagine but hard to understand, and vice versa.
I suspect that some people have a problem with the hypostatic union because of the idea that two things can’t occupy the same place at the same time. But it’s important to remember that the divine nature, being spiritual, takes up no physical space.
If Jesus is God, then either he is like a centaur, being half God and half man; or he is fully God and fully man. Although, theoretically, an animal could be half human and half horse, there’s no way he can be fully human and fully horse, because part of the nature of human and of horse is to have a physical body, and he can’t have two physical bodies at the same time and in the same place.
But since it is not of the nature of God to have a physical body, there is no necessary conflict in conceiving of Jesus as fully God and fully man.
A nature is that by virtue of which a thing acts as it does. Thus, human beings walk because it’s our nature to have legs, and we think because it’s our nature to have an intellect. Jesus’ having two natures means that in addition to the things he does by virtue of being human, there are also things he does by virtue of being God.
He’s not half God, as if he can act like God but with only half the power. And he’s not half human, as if he only has one eye, one ear, one arm and one leg. He’s fully human, with a whole human body and intellect, and he’s also fully God, having existed for eternity and possessing infinite power, etc.
I don’t see the problem. I can understand people not believing this doctrine, if they already believe something which contradicts it (such as that God and man are of the same nature but at different stages of development). But I don’t see why it must be thought of as incomprehensible or self-contradictory.