In 2009 Christian apologist Matt Slick (carm.org) phoned in to Matt Dillahunty’s live cable access TV show in Austin Texas, The Atheist Experience, to discuss his theory of logical absolutes. You can watch the debate here.

The debate basically met with agreement up until the statement made by Slick that logical absolutes are conceptual in nature, which Dillahunty disagreed with. Although Dillahunty accepted Slick’s view that logical absolutes are not dependent on human subjectivity, he held that since they were abstract, they were not conceptual in nature at all. He argued that logical absolutes would apply even if we lived in a universe without humans (or, he added, physical objects).

What is well accepted by most philosophers is that the rules of logic have an abstract and universal nature. This is not to say, however, that the rules of logic have an external nature. Something can be universal (that is, shared by humans) without implying that it is external to human subjectivity. This is the difficulty in the positions advanced by both Dillahunty and Slick, as they assume that since the rules of logic are abstract, then they must not be dependent on human subjectivity.

Some philosophers contend that logic is akin, if not equivalent, to language, which follows rules (i.e. grammar) relating to how words are to be correctly structured in order to be valid statements, and that these rules are perceived independently of any particular individual. Yet, they are not external to human subjectivity in general, as linguistic rules can only be processed and applied through a human mind.

Slick is guilty of the same slippage here as Dillahunty. In moving from “Logical absolutes are not dependent upon human minds”, to the statement “they are not the product of human thinking”, he has committed a category fallacy. Those two things are not necessarily commensurate. To say that something is not dependent upon human minds can be understood in two senses. The first – and which most philosophers would accept – is that the rules of logic are not dependent on individual subjectivities. This is quite different from the claim that the rules of logic are independent from all human subjectivities.

Because both participants accept this shift to externality (Dillahunty because he is a realist, and Slick because he is a deist), the debate then comes down to arguing where this externality resides. This gives Slick the upper ground, because he does not then need to make the additional step – as Dillahunty does – of claiming that logical absolutes are non-conceptual in nature.

In the next article of this series, I will look at how logical rules share similarities to mathematical properties and physical laws, and involve the same issue of their dependence on human subjectivity.