How Do I Know that I Know?

By Richard Howe In 2013, I had the privilege of participating in both a written and panel dialog/debate with K. Scott Oliphint of Westminster Seminary and Jason Lisle founder of the Biblical Science Institute. Oliphint is a theologian and Lisle is an astrophysicist. Both are proponents of the apologetic method of Presuppositionalism in the tradition of Cornelius Van Til. Recently a student of mine asked me how I would respond to one of Jason Lisle’s challenges to me. I contend that all knowledge begins in the senses and is completed in the intellect. (Lest the reader misunderstand what I specifically mean by my use of the term ‘knowledge’ in this context, he is encouraged to read my blog article titled “Discussing Aquinas” here.) Lisle asked: “How does he know that he’s not in the ‘Matrix’ and that his sensory experiences have nothing to do with the real world?”[1] In helping the student by answering Lisle’s question directly, I also wanted to take the occasion to set Lisle’s question in a broader philosophical context to see how his question conceals certain philosophical assumptions that need to be surfaced and examined. Lisle’s question is ultimately impossible. I claim that it is undeniable that one can know reality through the sensory faculties—seeing, hearing, tasting, touching, smelling. The reader should note the subtle shift here. Above, I said that all knowledge begins in the senses. Lisle’s challenge is in effect asking how any knowledge can arise from the senses. More to the point, Lisle is asking how I can know that my senses are reliable—how can I “know” that I “know.” Lisle’s challenge is less complicated to answer than my original contention is to defend. I will take the less complicated route here. It remains that the fact that any knowledge can arise from the senses is a necessary condition for the claim that all knowledge arises from the senses (and is completed in the intellect).[2] The most common responses or challenges to my claim are this one that Lisle poses (how do you know your senses are reliable?) and questions to the effect of how can one acquire knowledge about non-physical truths like logic, morality, metaphysics, and God by means of the senses. He makes the charge (in teeing up his challenge) that I have “tacitly presupposed (among other things) that our senses correspond to reality.”[3] As we shall see, I have done no such thing. Lisle’s question implies that I could know that I know reality only if I know that my senses are reliable. Let’s momentarily grant his point for the sake of argument. I’ll come back to answer it directly. For now, consider what questions one would need to ask about Lisle’s challenge. Since my senses are themselves part of reality, how could I know that my senses are reliable when I claim that it is in them that my knowledge of reality has its origin? In other words, whatever means (be they other faculties besides the sensory faculties or something else) I use to deliver to me the conclusion that my senses are reliable, I would then have to ask how I know that this means was itself reliable. By whatever means #2 I might offer as to how I would answer that, how could I know means #2 is reliable when it tells me that the first means was reliable in telling me that my senses were reliable in telling me about reality? If I posit means #3 to tell me that means #2 is reliable when it tells me that the first means is reliable when it t...