Editor’s note: We are delighted to present this excerpt from the new book Sacred or Secular: The Pro-Life Case for Grounding Human Value in the Image of God, by Jacob Vazquez, with a foreword by J. P. Moreland.
One of the central assumptions of contemporary naturalism is that Darwinian evolution is sufficient to explain every aspect of human existence. While this claim is commonly applied to the origin and diversity of biological life, its implications extend much further. If naturalism is true, then consciousness, rationality, free agency, and even our deepest moral convictions must ultimately arise from unguided physical processes shaped by evolutionary history.
Sacred or Secular: The Pro-Life Case for Grounding Human Value in the Image of God argues that this assumption deserves far more scrutiny than it typically receives. More importantly, it contends that the abortion debate unexpectedly exposes one of naturalism’s deepest explanatory weaknesses.
The book develops what I call the Imago Dei Argument from Personhood (IDAP). Rather than beginning with biblical texts about the unborn, the argument begins with a remarkable point of agreement between opposing sides of the abortion debate. Both pro-choice naturalists and secular pro-life advocates commonly appeal — either explicitly or implicitly — to consciousness, rationality, and intrinsic human dignity as morally relevant features of personhood. Yet these same features raise profound philosophical questions. Why does consciousness exist at all? How can purely physical processes produce genuine rational thought rather than merely adaptive behavior? Why should human beings possess intrinsic worth instead of value derived solely from evolutionary advantage or social consensus?
A Choice of Worldviews
The central question, then, is not simply whether these characteristics exist. It is which worldview best explains and grounds them.
Consider the writings of Peter Singer, one of the world’s most influential defenders of abortion and infanticide. Singer argues that unborn children are not persons until they possess capacities such as sentience or self-awareness. Yet these criteria presuppose realities that his own naturalistic framework rooted in Darwinian evolution does not adequately explain. Consciousness is assumed to exist and to possess objective moral significance, but little attention is given to how a worldview of blind, purposeless physical processes can account for either. The same observation applies to many contemporary defenses of personhood. The traits used to justify moral status are frequently assumed rather than ontologically grounded.
Inference to the Best Explanation
This observation forms the heart of the IDAP. If consciousness, rationality, and intrinsic human dignity are genuine features of reality — as both sides of the abortion debate largely acknowledge — then an adequate worldview should not merely recognize them but explain why they exist and why they possess objective moral significance. The question becomes one of inference to the best explanation: Which worldview best accounts for the very features used to define human personhood?
Here naturalism faces persistent philosophical challenges. Over the past several decades, numerous philosophers — including many outside the Christian tradition — have acknowledged the explanatory gap surrounding consciousness. Likewise, the reliability of human rationality under evolutionary naturalism has been questioned by philosophers such as Alvin Plantinga, who argues that if our cognitive faculties are selected primarily for survival rather than truth, confidence in those faculties becomes difficult to justify. Human dignity presents an equally significant challenge. Darwinian evolution may describe the emergence of cooperative behavior, but it does not establish that every human being possesses equal and intrinsic moral worth.
A Markedly Different Picture
The Christian worldview offers a markedly different picture. The doctrine of the Imago Dei provides a unified metaphysical foundation for consciousness, rationality, free agency, and intrinsic human dignity. Human beings possess objective value not because of what they presently do, but because of what they are: creatures uniquely made in the image of God. This grounding preserves the equal dignity of every member of the human family — from the embryo to the patient with advanced dementia — and avoids reducing human worth to performance, cognitive ability, or social utility.
Rather than treating abortion primarily as a political or biological dispute, Sacred or Secular argues that it is fundamentally a worldview question. Before we can determine who counts as a person, we must first ask which worldview best explains what a person is. The book concludes that the very characteristics invoked throughout the abortion debate — consciousness, rationality, and intrinsic human dignity — function as recalcitrant facts for naturalism while fitting naturally within the Christian doctrine of the Imago Dei. If that conclusion is sound, then the abortion debate points beyond biology to something far deeper: the worldview that best explains human nature itself.