The application-conditions for design inferences: Why the design arguments need the help of other arguments for God’s existence

Abstract

Proponents of design arguments attempt to infer the existence of God from various properties or features of the world they take to be evidence of intelligent design. Thus, for example, the fine-tuning argument attempts to infer the existence of a divine designer from the improbable fact that life would not be possible if any of approximately twoto three-dozen fundamental laws and properties of the universe had been even slightly different. Similarly, the argument from biochemical complexity attempts to infer the existence of a divine designer from the improbable fact that living beings frequently instantiate what proponents call irreducible specified complexity. In this essay, I argue that we are justified in making design inferences only in contexts where there is already strong independent reason to think that there exist intelligent agents with the ability to bring about the occurrence of the relevant entity, feature, or property. Only in such contexts is there sufficient information to justify assigning a probability to the design hypothesis that is higher than the probability that we are presumably justified in assigning to the chance hypothesis. Accordingly, design arguments implicitly presuppose that some other argument for God's existence justifies assigning a probability to the design hypothesis that is larger than the probability we can assign to the chance hypothesis. What this means, contra the intentions of proponents, is that design arguments for the existence of God cannot stand by themselves.