Logic and Interpretation

In his essay, “The Role of Logic in Biblical Interpretation,” Paul Helm claims that you can’t understand a document without employing logic. He argues that to understand a work, one must possess certain capacities all of which depend on the use of logic. If so, then to understand the Bible, one must employ logic.

In sum, Helm’s overall argument runs as follows:

  1. S understands sentences of language, L, in work, W, iff S (i) knows the truth conditions for sentences of W, (ii) can say what the sentences do not mean, (iii) knows what the sentences imply, and (iv) can supply a synonymous translation of sentences in W.  
  2. S possesses (i) – (iv) only if S employs logic.
  3. Therefore, S understands sentences in W only if S employs logic.

According to Helm, there are at least four capabilities necessary for understanding a declarative sentence. First, an interpreter must posses the ability to say under what circumstances the sentence would be true (implying knowledge of the circumstances under which it would be false). Second, the interpreter possesses the capacity to say what the sentence does not mean (implying knowledge of what the concepts employed in the sentence do not mean. i.e. ‘mat’ does not mean ‘moon.’). Third, the interpreter possess the ability to say what the sentence implies (if ‘the cat is sitting on the mat,’ then ‘at least one cat is on something.’) Finally, the interpreter possess the capacity to produce a cognitively synonymous translation.

In sum, S understands literary work, W, iff S knows the truth conditions for sentences of W, can say what the sentences do not mean, knows what the sentences imply, and can supply a synonymous translation of sentences in W.  

Having dealt with (1), it is time to turn to (2). Why think that to posses any of the capacities for understanding so far enumerated, one must employ logic? According to Helm, to employ logic is to employ the “basic, formal principles of thought and deductive reasoning.” Such principles include the following:

  1. Everything is self-identical
  2. Indiscernibility of identicals 
  3. Law of bivalence 
  4. Laws of inference (e.g. Modus Ponens)
  5. Law of non-contradiction

It turns out that the capacities required to understand the meaning of sentences require the use of these logical principles.

For example, if possessing the ability to say under what circumstances the sentence would be true implies knowledge of the circumstances under which it would be false, then one must apply the principle of bivalence. Bivalence is a formal principle according to which any proposition has only one truth value – either true or false. 

Or, consider the capacity to say what a sentence implies. The interpreter possess the ability to say what the sentence implies only if the interpreter employs a logical rule of inference.

One might reply that some sentences in a work are not declarative. Thus, there are some sentences in a work that do not require the capacity to know their truth conditions. For example, what about interrogatives and imperatives? In a footnote, Helm suggests that a similar condition would obtain involving reply-conditions for interrogatives and compliance-conditions for imperatives. Even if we limit Helm’s proposal to those sentences that are either clearly declarative or imply a declarative sentence (as in rhetorical questions), we have a fairly substantive thesis about much of the contents of a given work.

Like any other thesis, it is not without its challenges. Helm responds to five. According to the conventionalist challenge, all logical systems are the product of conventions. However, if logical principles are conventions, then other principles should be available. But there are no alternatives. One either employs the principles or one doesn’t but one doesn’t employ an alternative set of principles. There are no ‘biblical’ logical principles as opposed to logical principles themselves. This does not entail that all the logical principles we employ are correct. It only implies that whatever logical principles are, they are not reducible to conventions. 

According to the warmth challenge, logic is cold, but the Bible is filled with the personal and relational speech. Helm replies that to know the meaning of the personal sentences, one must employ logic. For example, to know what ‘I love you’ means involves knowing that it doesn’t mean ‘I hate you.’ Further, the subjective response to scripture is independent to the understanding of scripture. One can be unmoved by the gospel and remain in rebellion against God yet understand the cognitive content of scripture. However, a believer will also desire to obey scripture. 

According to the relativist challenge, logic is imposed on the biblical authors. We fail to read them as they would want. Instead, we read them as fellow enlightenment thinkers. In reply, Helm argues that it is false that the biblical authors did not employ normative principles of logic. An examination of the text reveals an adherence to the laws of logic. Someone might say that the biblical authors may have employed those principles, but that does not make them normative. In reply, the objector must now provide an alternative (see above). 

According to the economic challenge, logic complicating matters. What does this objection amount to? Helm compares causal explanations with deductive arguments. The best causal explanation for a given phenomenon meets a set of criteria including parsimony. The challenge appears to be that by inferring doctrines from scripture, one breaks this rule. The objector says that “to maintain the doctrine of the Trinity as scriptural unnecessarily complicates matters” (884). But this is to conflate what is logically implied by scripture with what causally explains it. Logical implication is independent from causal explanation. The following propositions are expressed in scripture: God is numerically one. The Father, Son, and Holy Spirit are identical to God and non-identical to each other. The logical implication is the doctrine of the Trinity. It is not a causal explanation. 

Finally, according to the dogma challenge, if one uses logic to interpret scripture, one will treat scripture as dogma. This objection points out that one treats the statements of scripture as true whether or not they are rationally assessable. In reply, Helm claims that it is false that statements in scripture are not rationally assessable. Further, it is irrelevant because the difference between dogma and non-dogma is irrelevant to interpretation. Interpretation using logic is only interested in the truth conditions for the sentences within a text. One does not need to treat scripture as true, one only need to know the truth conditions for those sentences if knowing the meaning of sentence is the same as knowing its truth conditions. Thus, an interpreter of scripture may also be a nonbeliever in the content of scripture. 

Assistant Professor of Philosophy and History of Ideas at Southeastern Baptist Theological Seminary and The College at Southeastern.