Not quite. The argument depends upon the assumption that biology is static--that is, it depends upon the assumption that the brains of 13-18 year-olds have always been different than those of individuals aged 30-60, for instance. For this argument to work, biology--or more specifically, neurobiology--must be "given." That is, the brain must be a stable entity that is not subject to change based on mental, spiritual or--as I am mostly interested in here--even cultural or societal forces.
There is, however, some reason to think this isn't the case. I'll provide three examples that call into question the static nature of corporeality:
The age of menarche has dropped from 15 or 16 to 12. Why? For one, women's bodies are bigger than they were 100 years ago. Presumably, even this is related to a general increase in wealth that allows for a more comfortable means of life. Not only that, but women's understandings of their own bodies has shifted dramatically during this time as well in light of new social and cultural forces. These forces have contributed to a dramatic reinterpretation of sexuality and its place in young girls' lives and have contributed to the dropping age of menarche. As Joan Jacobs Brumberg contends, "In reality, there is an interaction between biology and culture that is shaping the experience of contemporary girls in some critical and troubling ways."
Virginia Postrel points out that the Hutcheson Memorial Forest, which is full of oak and hickory trees, was originally thought to have been that way forever. As a result, researchers moved to keep it from human interference. However, when maples began to take over the oaks, further research revealed that in the past, Indians had burned the underbrush in order to travel through the forest. According to ecologist Daniel Boktin, this human involvement "cleared the understory, favored oaks over maples, and created the open forest of tall trees believed by naturalists in the early sixties to be original, constant, and unaffected by human influence." Here, the existence of the physical order is clearly not "given." It has been, and continually is, affected by human presence and institutions.
There is some evidence that those young people who were given music lessons didn't merely show a better understanding of music, but demonstrated more improvement in general memory and cognitive development. That is, music doesn't simply help our IQ--it actually changes the physical brain states and the overall functioning of the brain (mind). Of course, if music, then why not the host of other influences--tv, parents, etc.--that we encounter every day?
In essence, the notion that the body is just the body is dubious. And the notion that the only sources of physical change are physical is equally doubtful. The proposition, of course, may not be that interesting to those who adhere to the theory of evolution. For them, the physical structure--the form of matter, if you will--of natural entities is always in flux. But still, this leaves the causes of such changes as an open question. What implications might the non-fixity of corporeality have for us? It means that we can't turn to science alone if we want to understand the physical world, as the causes of physical phenomena may not be physical. And here I do not mean to enter into an "intelligent design" debate, but rather simply point out that in attempting to understand the reason for the particularities of adolescent brain structures (for instance), we should not be overly reductionist in our attempts. Rather, if we understand the physical world, we must understand the whole world--the historical, mental, social and (yes, even these) theological forces that shape the physical world. On a theological level, the question for Christians is not, "body or not body?" but rather, which type of body? A body governed and empowered by the Spirit or a body governed and empowered by the powers and principalities of this world? If the body isn't "given," then we must be aware of the ways in which culture shapes it and be prepared to reshape it according to the image of God.
It is my hope that I am wrong. I want corporeality to be "fixed." It would, if nothing else, make understanding the world far more simple. But if, as I have argued, it is not, then we need to ensure our approach to reality fits reality itself. And that means employing robust, multi-disciplinary accounts.
Matthew Lee Anderson is an Associate Professor of Ethics and Theology in Baylor University's Honors College. He has a D.Phil. in Christian Ethics from Oxford University, and is a Perpetual Member of Biola University's Torrey Honors College. In 2005, he founded Mere Orthodoxy.