The pinch test is a simple one. In order to prove one’s existence in the real world, one pinches oneself. If the pinch hurts, then one is real and awake; if not, then the realness of one’s existence is in doubt or one is dreaming. Descartes would appreciate this argument as one of many which resonate with many of his ideas, particularly in Meditations. Descartes’ arguments regarding knowledge of being, existence and reality revolve around the senses, but Descartes does recognize the limitations of this approach. Unfortunately, the application of nearly every test that one can think of to prove that one is awake can be done, without success, when one is asleep. The pinch test is not much different than that. Dreams can be incredibly realistic, with clear visuals, and even smells and sounds. Various events that happen in dreams can result in a physical sensation; vertigo when falling or flying, or even hunger. Sometimes the sounds or sensory information from the external world will seep into the dream world, such as when one hears the buzzing of the alarm clock in one’s dream, but it is integrated so that the sound is cohesive with the dream reality. Such phenomena make it truly different to determine if we are dreaming, and by the same token we should assume that it is very difficult to prove to ourselves that we exist and are world is real, given that we can’t really even prove that we are awake.
There are other technical aspects that Descartes did not discuss, as they are founded on scientific developments that were not available in his time. This includes the existence of a condition where people do not feel pain or sensory touch, and therefore would never feel the pinch of the pinch test. It also includes psychological research on expectations, and how these can ultimately create experience. Because of such psychological findings, we know that if we expect the pinch to hurt, then it probably will. Despite not having this knowledge available, Descartes was able to lay out an argument that is aligned with such discoveries.
With regard to the reliability of the pinch test, Descartes might conclude that further testing and thinking were necessary, and that the reasoning and arguments regarding that should be made ever clearer. Dreaming poses a great difficulty to determining and defining reality. Where distinct sensory perceptions are evidence regarding our existence in reality, they are not definitive as a test (Markosian, 2014). More is required; that we think and are conscious of ourselves; that we are conscious of conscious others; that are interactions align with the physics of the real world- these are important pieces of evidence as well. Descartes would come to this conclusion as the importance of the question lies not in the answer, but in the discussion which one uses to broaden the possibilities of how we think about existence.
In my personal opinion, Descartes has come with an excellent line of reasoning, but it is not one that is based on resolving the dilemma of determining if one is real and existing, or just dreaming, or not existing at all. Rather, the reasoning is intended to broaden the questions that we ask with regard to how we know that we ARE. Most importantly, it makes clear the importance of skepticism and continually challenging what we know in order to really determine what is true and what is not. Descartes concept is that we will never really know, and given that we might as well never come to conclusions; what is important is that we challenge and reason through the possibilities and gain insight with regard to such metaphysical conundrums.
- Markosian, N. (2014). Do You Know That You Are Not a Brain in a Vat?. Logos & Episteme, 5(2), 161-181.