We next part of the chapter the book discusses is Cogito, “I think, therefor I am” means that the act of thinking presupposes the existence of the subject – the thinker. This is important because it requires no other predicates. The mere act of questioning means that there is a questioner. The reading material then moves to the criticisms of cogito. The most universally accepted opinion is that the conclusion is extremely limited. Descartes was incapable to express his doubts. Thus, the attempt to doubt anything would be necessarily self-defeating.
The next theory for discussion is “Representative Realism”. Representative Realism argues that we experience reality indirectly by perceptions that represent the real world. So, if we see a brown table, what we are actually seeing is not the table itself but a representation of it. Criticisms of representative realism argue that it is difficult to clearly define what a real or objective experience might consist of because every description is also another viewpoint. This is the same with anything, from physical objects to ideas.
The problem then seems to be that if we can only ever experience perceptions of objects (what Locke would have called secondary qualities), who is to say that they actually exist? The author the goes into a discussion of Idealism. Idealism is a group of philosophies which assert that reality, or reality as we can know it, is fundamentally mental, mentally constructed, or otherwise immaterial. There are several criticisms of this theory, starting with hallucinations and dreams. The book uses the example of a guitar, and the visual experience. This whole section is pretty left field, so I won’t try to explain it beyond my knowledge.
Solipsism is the next argument that criticizes representative realism. Solipsism is the view that all exists in my mind and the creation of everything else is of your own invention. The last criticism of representative realism is the “simplest explanation”, this explains that we might want to know what is the cause of these experiences and where did they come from? It argues that it is God, not physical objects that cause us to sense experience. All of this criticism and skepticism of representative realism leads us to Phenomenalism, which is a hypothesis of realism.
Phenomenalism, like idealism, is based on perception. Like Idealism, it argues that our knowledge about the world comes through our senses. Furthermore, it also shifts knowledge about the world away from any talk of “the object itself” and replaces it with our experiences of it. This is difficult to grasp because it is a theory of truth and not just an account of perception. There are two criticisms of Phenomenalism in our book, the first is the difficulty of describing objects, and the second is the objection of solipsism and the Private Language Argument. The chapter then turns to Causal Realism.
Causal realism assumes that the causes of our sense experiences are physical objects in the external world. Causal realism takes as its starting point the observation that the main biological function of our senses is to help us find our way around our environment. It is through our senses that we acquire beliefs about our environment. There are two criticisms of Causal Realism in our book, they are “Experience of Seeing” and “Assumes Real World”. The qualitative aspect of seeing something is pretty self-explanatory and as the old saying goes, “Seeing is believing! The Assumes Real World objection is more towards everyone’s own perception of what’s real and what’s not.
This chapter certainly didn’t lack theories and objections to choose from. I personally learn towards the “seeing is believing” argument. The main criticism of causal realism is that it doesn’t take actual account of what it feels like to actually see something. They don’t take into account the qualitative aspect of sight. It reduces the experience of seeing something to more of a form of information gathering. It’s awfully hard to devalue what it is that YOU see. That’s just one man’s opinion on how the world works.