A Cartesian Objection Against Materialism

Descartes' Argument from Doubt Against Materialism
 
1. Descartes supposed his body to be nonexistent.
2. Descartes did not suppose himself to be nonexistent.
3. Therefore, (1) and (2). [1,2 Conj]
4. If (1) and (2), then Descartes was not identical to his body.
5. If Descartes was not identical to his body, then TM is false.
6. Therefore, TM is false. [3,4,5 MMP]

• Be able to provide a rationale for premise (1) based on Descartes' First Meditation.
• Be able to provide a rationale for premise (2) based on the early paragraphs of Descartes' Second Meditation.
• Be able to utilize the definition of 'x is identical to y', the Principle about Identity, and the property of being supposed by Descartes to be nonexistent in the construction of a robust, clear rationale for premise (4).

 
"As a young man, Oedipus was told that his father had long been dead. One day, as Oedipus was on the highway to Thebes, he met a stranger. The stranger was a nasty old guy who would not let Oedipus pass by him on the highway. Oedipus became upset and killed the stranger on the road. Years later, Oedipus was told that his father was the stranger on the road. Partly because of killing his own father, and partly for other reasons, Oedipus poked out his own eyes."

Oedipus Argument
 
1. Oedipus supposed his father to be nonexistent.
2. Oedipus did not suppose the stranger on the highway to be nonexistent.
3. Therefore, (1) and (2). [1,2 Conj]
4. If (1) and (2), then Oedipus' dad is not identical to the stranger on the highway.
5. Therefore, Oedipus' dad is not identical to the stranger on the highway. [3,4,5 MMP]

This argument is intended to be a parody of the Argument from Doubt. How might your evaluation of this argument be relevant to your evaluation of the Argument from Doubt?