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    On Stuff

      1. Quantum physics
      2. Dreams
      3. Tulpas and Hinduism
      4. Geroge Berkeley
      5. Questions for you


It is a very challenging and difficult task to seriously question a belief that is considered to be completely obvious. The common belief in the physical existence of material things is just such a belief. We would probably consider it a ludicrous request if anyone were to ask us to question or doubt the existence of physical things. And yet that is exactly what I will be asking you to try to do.

To help you with this difficult task I offer you here three pieces of evidence that our belief in the existence of physical stuff may be mistaken. The three evidential pieces come from three completely independent sources, yet all three sources point to the identical conclusion: viz., what we think of as physical matter probably does not actually exist. The three pieces of evidence are quantum physics, dreams, and the Hindu concept of tulpas.

1. Quantum physics

Physics is the scientific study of physical matter, so if there is any modern science to which we should turn to learn about the existence of physical matter, it would probably be physics. To learn what quantum physics teaches us about the existence or non-existence of physical matter, please read the mini-lecture on quantum physics.


Please break here and continue this lecture after completing your reading of the mini-lecture on quantum physics.
Thank you.

2. Dreams

When we think closely about the kinds of experiences that we all have for several hours almost every night of our lives, we might also come to wonder about the ultimate realness of physical matter. After all, the worlds we experience in our dreams are also worlds which seem to be composed of physical matter (they definitely seem that way while we are experiencing them). But when we examine more closely those seemingly "physical" worlds of our dreams and the seemingly "physical" things in those dream worlds, we see that what appeared to be physical matter while we were experiencing it is in fact made up only of a kind of thought-stuff.

To help us look at this dream-reality question more closely, I ask you now to go read the entirely true story titled "My Dream," and to respond to the questions at the end of that story. So please go now to "My Dream," read it closely, and then when you've finished that, come on back here.


Please break here and continue this lecture after completing your reading of "My Dream."
Thank you.

3. Tulpas and Hinduism

The Hindu concept (or experience) of the tulpa is yet another piece of evidence that might lead us to question the actual existence of physical matter. If the entire physical cosmos is, according to the ancient teachings of the Hindu tradition, one great tulpa, then its status as physical matter is definitely questionable.

To understand what a tulpa is, and what its place is in the Hindu world-view, please read the mini-lecture on tulpas.


Please break here and continue this lecture after completing your reading of the mini-lecture on tulpas.
Thank you.

4. George Berkeley

I originally said that there would be three pieces of evidence for you to take into account when you are considering the question of the existence of physical matter, but there is one more thing for you to consider also. George Berkeley's philosophical writings are perhaps the most famous philosophical examination of this question about the existence of physical matter, and he concludes that common sense shows us, if we think about it clearly, that physical matter simply does not exist. His arguments are not abstruse or difficult, but are actually founded entirely on simple common sense. He argues, therefore, that simple common sense, if we think about it carefully and closely, will lead us to the conclusion that physical matter does not exist, and that the entire "physical" world is instead made up of a kind of thought-stuff.

George Berkeley (1685-1753) wrote two primary works on this question. Three Dialogues Between Hylas and Philonous (1713), written when he was 28 years old, is a set of three short conversations between Hylas, who represents people who believe in the existence of physical matter, and Philonous -- lover of mind -- who represents Berkeley's point of view. A somewhat more extended analysis of these arguments is presented in his earlier work,A Treatise Concerning the Principles of Human Knowledge (1710) written when he was 25 years old.

Most people find the Three Dialogues more palatable and easier to read, but some students have told me that they liked The Principles better.


Now, two questions for you to mull over a bit and respond to in the classroom.

1. Even if you found none of these three pieces of evidence entirely persuasive, which of the three (or four, if you went off and read some Berkeley) would you say was, for you, the most meaningful. That is, which of the three pieces of evidence would be the one most likely to lead you to question whether or not physical matter truly exists?

2. And what was it about that argument that was persuasive to you?