Reading One: Descartes’ Meditations.
Descartes was a mathematician. He wanted to refute skepticism by creating a solid foundation for the things we know. Descartes wanted to know if there was anything that could be believed without the possibility of doubt. He thought the senses were unreliable. But what about logic and math? As a thought experiment he imagined the existence of an all-powerful demon who could make even logic and math unreliable. In such a world is there anything that we still could know for sure? Descartes answers yes. We can know that we exist, and that we are thinking. We just cannot be mistaken about that.
Question One: Why does Descartes believe that our senses are unreliable? Why does he think that everything we experience could be a dream?
Question Two: Descartes imagines an “evil demon” who has the power to manipulate our understanding of the world. What is the one thing we could still know with absolute certainty?
Question Three: Descartes says the only thing we can know for sure is our mind, which is not physical. We can never be sure that the physical world exists. Is he right? Are physical things and mental things fundamentally different?
Reading Two: Grau, Evil Demons, and the Experience Machine.
Christopher Grau uses the film The Matrix as the basis for a discussion about skepticism. If you haven’t seen the Matrix, it’s about Neo, a computer hacker who discovers that “reality” is actually an illusion created by super powerful computers who have tapped into our brains and are feeding us false sensory data. This might sound familiar, since it a similar idea to Descartes’ “evil demon.” Of course, the filmmakers have read Descartes. How do we know we are not in the Matrix? What difference would it make? How do we know we are not just a brain in a vat sitting on a shelf in some mad scientist’s basement? We don’t really. Is that a problem?
Question Four: Should we take the “Matrix” hypothesis seriously? Would finding out that you were in the Matrix world change the way you live your life?
Question Five: Imagine a machine that could give you whatever pleasurable experiences you could want. Assume that you could not distinguish your experience in the machine from reality. If given the choice, would you prefer the machine to real life?
Reading Three: Popper Conjectures and Refutations
In this reading we are talking about science. Scientific investigation is empirical in nature. That is, unlike rationalism, science is based on observation and testing. Empiricists believe that our senses are not perfect, but they are good enough to explore and understand the world, even if we cannot be absolutely certain about scientific knowledge. This brings us to an important point. Scientist can never be sure a theory is 100 percent correct. Let me explain why:
Imagine for a moment that you wanted to prove the theory “all swans are white.” You send people out to look for swans, and everyone reports seeing only white swans. How many observations would you need before you could claim your theory was true? Ten, a hundred, a hundred thousand? No matter how many white swans you see there is always the possibility that there is a different colored swan out there. You simply cannot count every swan. So scientists don’t look for confirmations of their theory, they look for disconfirmations. To use our example, we should not look for white swans, we should look for the black swan. Because if we see the black swan we know our theory is WRONG.
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In other words, scientists can never really know when their theory is right, but they can know immediately when it is wrong. For Popper this is the strength of science.
What Popper is worried about:
Popper is concerned with fake science, what he calls pseudo-science. Many ideas, like parapsychology (ghost hunting) for example, claim to be scientific. Are they? Popper comes up with a way to distinguish real science from fake science. Falsifiability. A theory is not scientific unless we know what evidence could prove it wrong. If a theory is incapable of being proved wrong (like astrology) it cannot be scientific.
Question Six: According to Popper, is astrology a real science? Why or why not?
Question Seven: According to Popper, why are disconfirmations of a theory more important than confirmations?
