What is a model?
The question in the title of this paper raises an initial question: in general how should we go about the task of relating theological truths to current scientific theories? Theological truths revealed in Scripture are eternal infallible truths, valid for the whole of humanity for all time, although human interpretations of Scripture are not infallible and may change with time over issues that are not central to the Gospel.
Scientific theories, by contrast, represent the current ‘inference to the best explanation’ for certain phenomena as judged by the scientific community based on criteria such as the interpretation of observations, experimental results, mathematical elegance and the ability of theories to generate fruitful research programmes. Scientific theories are not infallible and will certainly change. However, change does not necessarily imply replacement. Usually scientific theories are not replaced, but modified. In this respect they are often likened to maps that incorporate many different types of data: the maps are revised, as required, to incorporate new data and are improved in the process.
Scientists sometimes use the word ‘model’ to propose one big idea, or a cluster of ideas, that together help to explain certain scientific data. To the despair of philosophers of science, the use of such words in scientific discourse can lack precision. The word ‘model’ is a case in point, its use sometimes overlapping with the term ‘theory’. Usually, however, ‘model’ has a more focused meaning: the way in which certain sets of data can be rendered coherent by explaining them in terms of a physical, mathematical or even metaphorical representation.
During the early 1950s there were several rival models describing the structure of DNA, the molecule that encodes genes. Linus Pauling proposed a triple-helix model. But Jim Watson and Francis Crick had the huge advantage that they obtained the X-ray diffraction pattern results of DNA in advance of publication from another scientist called Rosalind Franklin. The double-helix was in fact the only model that would incorporate all the data satisfactorily, as Watson and Crick published in their famous one-page Nature paper in 1953. Since that time everyone has known that DNA is a double-helix, it’s really not a triple-helix or some other structure. In science models are very powerful.
Not all scientific models win the day so decisively. For many years in my own field of immunology there were endless discussions about how the class of white blood cells known as ‘T cells’ are educated within the body to attack foreign invaders but not (usually) to attack ‘self’, meaning our own tissues. Those discussions are now virtually over because the general model that has emerged explains most of the data quite well, bringing in to the story research results from many different laboratories. But the successful model that prevails is far more ‘messy’ than the exceptionally elegant double-helical model for DNA. The most successful models are not necessarily the simplest. The best models are those that explain the data adequately.
Sometimes rival models exist for long periods of time in the scientific literature because they explain the data equally well. In that case a given model is said to be ‘under-determined by the data’. Everyone agrees with the data that do exist - the disagreement is about how to fit the data together to create the best model. Eventually new data emerge that count in favor of one model rather than another, or that decisively refute a particular model.
When we come to the question as to what ‘Biologos model’ might best address the relationship between the Adam of Genesis and the anthropological and genetic account of a humanity that did not have a single couple as the source of its genetic endowment, then we need to keep in mind these various ways in which the term ‘model’ is deployed in scientific discourse. We will start with an initial ground-clearing question: “Is model-building appropriate in relating theological and scientific truths?” and, having given an affirmative answer to this question, we will then go on to consider what model might be the most appropriate for relating the theological and scientific narratives.
Is model-building appropriate?
There are some who would maintain that the truths presented by the early chapters of Genesis are theological truths that are valid independently of any particular anthropological history. The purpose of the Genesis texts is to reveal the source of creation in the actions of the one true God who has made humanity uniquely in His image. The Genesis 3 narrative of man’s disobedience is the ‘story of everyman’. We have all sinned and fallen short of the glory of God and this passage presents this truth in a vivid narrative style that is about theology rather than history.
Those who adopt this position may also point to the dangers of a ‘concordist’ view of biblical interpretation. The term ‘concordism’ (in its traditional sense) generally refers to the attempt to interpret Scripture inappropriately using the assumptions or language of science. Calvin famously countered such tendencies in his great Commentary on Genesis, remarking on Chapter 1: “Nothing is here treated of but the visible form of the world. He who would learn astronomy and other recondite arts, let him go elsewhere.” But the term ‘concordism’ is also sometimes stretched to include virtually any attempt to relate biblical and scientific truths. Such a critique appears to be a step too far, for in that case our theology becomes too isolated from the world, contrasting with the famous ‘two books’ analogy in which the Book of God’s Word, the Bible, and the Book of God’s Works, the created order, both speak to us in their distinctive ways about the same reality. This powerful analogy has held sway for many centuries in the dialogue between science and faith, and the challenge is to see how the two ‘Books’ speak to each other, for all truth is God’s truth.
Building models to relate biblical texts to science requires no concordist interpretations of the text (in the traditional sense of the word ‘concordist’). The disciplines of both science and theology should be accorded their own integrity. The Genesis texts should be allowed to speak within their own contexts and thought-forms, which are clearly very distant from those of modern science. We can all agree that the early chapters of Genesis exist to convey theology and not science. The task of models is then to explore how the theological truths of Genesis might relate to our current scientific understanding of human origins.
The models that we propose are not the same as the ‘data’. On one hand we have the theological data provided by Genesis and the rest of Scripture, true for all people throughout time. Uncertainty here arises only from doubt as to whether our interpretations of the text are as solid as they can be. On the other hand we have the current scientific data that are always open to revision, expansion or to better interpretation. Nevertheless the data are overwhelmingly supportive of certain scientific truths, for example that we share a common genetic inheritance with the apes. The role of models is to treat both theological and scientific truths seriously and see how they might ‘speak’ to each other, but we should never defend a particular model as if we were referring to the data itself. The whole point of any model is that it represents a human construct that seeks to relate different types of truth; models are not found within the text of Scripture – the most that we can expect from them is that they are ‘consistent with’ the relevant Biblical texts. Let us never confuse the model with the truths that it seeks to connect to each other.
In practice any western reader of the Genesis text, raised in a culture heavily influenced by the language and thought-forms of science, can hardly avoid the almost instinctive tendency to build models or pictures in their heads as to what they might have observed had they been there when ‘it’ happened. This is the case irrespective of whether someone comes to the text as a young earth creationist, an old earth creationist, or some kind of theistic evolutionist. Given that we all tend to build models anyway, we might as well ensure that the model we do maintain has been thoroughly subjected to critical scrutiny. This is important not only for own personal integrity but also in the pastoral context in which we seek to avoid unnecessary cognitive dissonance in the minds of those under our pastoral care.