This charge means that when it comes to various theistic arguments, the believer typically attributes gaps in (especially) scientific knowledge to God. For example, when science can't explain how the universe came into being or how life originated on Earth, the Christian apologist is quick to point to God as a so-called cause or explanation. Thus the skeptic's accusation is that Christians do nothing more than give their ignorance a name–"God."
The naturalist (a person who believes that the physical cosmos is the ultimate reality) assumes that, given enough time, scientific exploration will discover a purely naturalistic explanation for what is now scientifically inexplicable. Oxford scientist Richard Dawkins responded in this way to Michael Behe's argument from irreducible complexity (the idea that the complexity of some life-forms cannot be accounted for through gradual evolutionary steps). Dawkins and other naturalists think that attributing scientific mysteries to God is illegitimate and it stifles scientific discovery.
Yet it is important to notice how entrenched naturalists are to their mindset and worldview. When it comes to science, only physical and material explanations are allowable (called methodological naturalism)–the supernatural is ruled out a priori (without examination). Also, some naturalists express excessive confidence that the future will explain reality. But they don't live in the future and it is illegitimate to appeal to the expected explanations of the future to explain present reality (what is needed is evidence in the present). This faulty form of reasoning constitutes the argumentum ad futuris fallacy ("accept this because future evidence will support it"). Ironically it might even be called "naturalism-of-the-gaps" reasoning.
Yet while modern science has been quite successful in explaining many particular aspects of the physical universe, some observers of the scientific enterprise think that it may have reached its limits when explaining the truly big questions of existence.1 Those limits may not allow answers to such profound questions as the origin of the universe, the origin of life, and the origin of consciousness. If this admittedly hotly contested perspective is even close to being true, then the grand natural explanations of science may have been exhausted. If so, naturalism as a worldview has not been able to adequately explain reality (especially its grand features). Given this pessimistic scenario (from a naturalist's perspective), it seems that appealing to the supernatural to explain reality may have some legitimacy after all.
Regardless of the course taken by naturalists, however, it should be noted that most sophisticated Christian theists don't engage in a god-of-the-gaps form of reasoning. Rather, Christian scholars appeal to God as an inference to the best explanation. In logic, this approach is known as abductive reasoning. Like inductive arguments, the abductive form of thinking yields only probable truth. Unlike induction, however, abductive arguments don't attempt to predict future possibilities. This careful thought process moves from the data, facts, evidence, and phenomena of the world to draw the most consistent and plausible explanation for these realities. This abductive form of logical reasoning is very similar to the way detectives, lawyers, historians, and scientists reason. For example, scientists sometimes postulate ideas that are unobservable in order to explain the data that is observed (consider dark matter). This approach posits the biblical God as the best explanation for all realities found in the world and in life.
One of Christian theism's greatest worldview strengths is the scope of its explanatory power. The historic Christian viewpoint accounts for the array of realities in nature and in human experience, including:2
- The universe–its source and singular beginning, order, regularity, and fine-tuning
- Abstract entities–the existence and validity of mathematics; the laws of logic; and scientific models (which include their correspondence to the time-space-matter universe as conceived in the mind of human beings)
- Ethics–the existence of universal, objective, and prescriptive moral values
- Human beings–their existence, consciousness, rationality, free agency, enigmatic nature, moral and aesthetic impulse, and their need for meaning and purpose in life
- Religious phenomena–humankind's spiritual nature and religious experience; the miraculous events of Christianity; and the unique character, claims, and credentials of Jesus Christ
These realities correspond to what the Bible teaches about God's creating the universe and, in particular, human beings in his own image (imago Dei). However, the Christian worldview overall does not naively assume divine activity or intervention as an explanation for whatever humans cannot yet explain, but rather offers a genuine and valid explanatory theory for the nature of life's realities. For many Christian thinkers, inference to the best explanation is a powerful and cogent approach to attempting to explain reality.
Skeptical philosophies of life such as naturalism have great difficulty explaining universal realities. On this basis, Christian theism's explanatory scope appears far superior to that of naturalism.