By Adam J. Pearson
Today, Ernie Jacobo asked me a fantastic question. His question was “why is logic so vital to human life?”
Logic separates invalid arguments from valid arguments. If the premises are true and the arguments are valid, then we have sound arguments. Sound arguments allow us to move from trustworthy premises to new conclusions. Logic is vital for the progress of all sciences and all inquiries into matters of life that admit of logical analysis.
Of course, logic has its limits; it can’t tell us if premises are true or false, only if they fit together in a way that allows us to validly derive a given conclusion from them.
Moreover, logical units, like sentences, can only handle discrete pieces of information at a time; thus, they must always leave something out. Logic places bits of information into frames so that we can handle them with our limited human rational capacities, but what is left out of the frame is always greater than what is encompassed by it.
With that said, discursive, word-based thinking without logic is muddied, confused, vague, ambiguous, and prone to drawing conclusions from premises from which they do not follow. Logic provides a reliable structure for our reasoning. It ensures that we are validly inferring what our premises bear out. It helps us to detect flaws in poor arguments just based on the way their sentences fit together. It is a kind of safety net for our thinking.
Of course, just as a net has holes through which some things fall, so does logic. Logic tells us that given sentences with certain truth-values arranged as premises and conclusions, certain arguments are either valid or invalid. It does not tell us, however, whether a given sentence is true or false; for that, we must look beyond logic into, for instance, empirical verification. We need to look to the data, or as Bertrand Russell used to say, “to the facts.” These facts are outside the scope of logic; the domain of logic is the basic logical structures of sentences, not their contents.