First, some clarification. We’ll start with what Intelligent Design is not:
Christian doctrine teaches that the universe, life, and human beings are created by God. That is, Creation was a deliberate act. Also, God is omniscient and omnipotent, and chose to exercise creation in a particular way. This is not the definition of Intelligent Design.
The teleological argument refers to a philosophical argument for the existence of God based on apparent design and purpose in the world around us. The universe and our place in it appear to be purposeful, and a purposeful creation suggests a purposeful Creator. Variations on this line of thinking can be traced back to before Plato, and it also features in the work of St Thomas Aquinas as one of his rational arguments for God’s existence. This is also not the definition of Intelligent Design.
So what is it?
Intelligent Design (or ID) maintains that “certain features of the universe and of living things are best explained by an intelligent cause, not an undirected process such as natural selection. Through the study and analysis of a system’s components, a design theorist is able to determine whether various natural structures are the product of chance, natural law, intelligent design, or some combination thereof.” (from intelligentdesign.org). In short, ID proponents claim that scientific inquiry can identify the intervention of intelligence in the evolutionary process.
The major feature of ID theory is the concept of “irreducible complexity”, specifically the idea that there exist structures and systems in nature that are so irreducibly complex that they could not have evolved step-wise via evolutionary theory.
In general, if we talk about trying to discern God’s influence in the universe scientifically, we have two major problems:
- There is no control group. Because God is omnipresent and not subject to human will, he can’t be excluded from part of an experiment to try and see what would happen “without” God’s intervention.
- More generally, science lacks the tools for investigating the supernatural. If we are suggesting that this “Intelligent Designer” is in fact God (and thus supernatural), then it is not clear that his influence could be discerned by scientific inquiry. If we’re thinking of aliens (or anything else non-supernatural), then I am not sure that “intelligence” would be the most easily identifiable evidence.
There are major theological issues with ID because it argues that God’s involvement in the universe is only necessary for stuff that we can’t explain by natural law. This is a classic “god of the gaps” argument, and it is lousy theology. Christianity teaches that God is involved everywhere. That God is the author and sustainer of the natural laws. ID suggests that God mostly lets the universe tick along by itself, but every now and then he steps in to design a bacterial flagellum, or whatever the latest example of irreducible complexity is.
Philosophically, the entire premise of ID seems doubtful. The central claim of ID is that the intelligence of the “designer” can be discovered scientifically. But if the designer used normal physical processes in any way, it is not clear that the influence of “intelligence” could be discerned.
Let us consider: I put a kettle on the stove and the water boils. By studying the stove and the kettle and the water (or steam if you wait too long), you can discover exactly how the chain of events unfolded. But it is not clear that the intelligent involvement and motivation could ever be discovered in this way. Did I want a cup of tea? Was I acting on instruction from someone else (in which case my actions involve no intelligence of my own)? Even if we look at the all physical actions that I undertook to make the kettle boil, it is not clear that the “intelligence” involved could ever be identified scientifically.
A note on irreducible complexity:
As a side note, I believe that irreducible complexity itself is an important avenue of study. But it is an avenue of study that involves evolutionary theory, not Intelligent Design. It is a challenge to see if there are limits to current understanding of evolution, and whether there are aspects of biological development that seem to argue against it. In the same way that dark matter and dark energy have forced us to reconsider a lot of what we thought about cosmology and gravity, it is possible that there could emerge a parallel biological paradigm which works in concert with evolutionary pressure to guide the development of life. But that is something for biological science to explore.
An argument against one theory is not an argument for another. So if we have a theory, we can make observations and conduct experiments that support or refute it. But refuting that theory does not support another: the two processes are independent.
The problem with ID is that it tries to argue against evolutionary theory, but gets a bit fuzzy on the details of what it is arguing for. ID proponents try to identify things in nature that can’t be explained by evolution, and then use such things to argue for ID. But what exactly is the unifying theory of ID?
“Sometimes, intelligence is involved rather than pure selective pressure based on reproductive fitness and survival. Other times, evolution just does its thing.”
But why was “intelligent design” applied in the case of a bacterial flagellum, and not elsewhere? For any explanatory power, a motivation for ID influence to appear in a particular biological feature would have to be clear prior to the knowledge that the specific feature appears to be irreducibly complex. This lack of a clear alternative theory means that, at most, irreducibly complex biological features can be seen as a challenge to current evolutionary theory. They cannot possibly be a positive argument for ID.