There is a concept in organic chemistry called conformational isomerism. The idea is that two different molecules can be made up of the exact same atoms, chemically bonded in the same ways, yet take slightly different forms. These different forms are called conformations. Conformations still have the same molecular formula, and maintain the integrity of their chemical bonds, but they act differently. For example, a certain molecule might be part of a chemical reaction, but it may have to be in a certain conformation in order to be part of the reaction. Any time it is in another conformation, it won't react.
Now, what does this have to do with The Dafe? You came here to read about The Dafe, did you not? Well, this is very relevant to Dave. When Dave adopts different napping positions, he is in effect adopting different conformations. When he adopts a certain napping position, he is the same Dave, made up of the same matter, and connected together in the same way that he always has been, but he reacts with the world around him differently depending on what conformation he has adopted.
For example, he might be splayed out on the bed, without a care in the world. This would not be a great time to attempt to pet Dave. If you petted his belly while in this position, you would likely find yourself scratched in short order.
Alternatively, he might be a RocketDave, at his most aerodynamic, ready for liftoff. In this case, you could probably pet Dave, but he still wouldn't be happy about it. He is focused on being a RocketDave here, so you shouldn't bother him.
|RocketDave! I miss the earth so much! I miss my wife!|
Despite the fact that Dave adopts so many different conformations at different times, at the end of the day, when it is time to be counted, Dave is the same Dave no matter what his current conformation is.