Phil 105: Science and Philosophy - Fall 2004 Lectures

!You will be sorely disappointed if you think that these are a substitute for attending class!

Topic Four: Time

1. Do the laws allow any constistent stories with portals?

• First bulb example: No
• Whatever its initial state, the bulb is switched on/off if it sees a bulb which is off/on emerging from the earlier opening of the portal – why is this impossible?
  

• Second bulb example: Yes
• Whatever its initial state, the bulb is switches to the inverse brightness of a bulb emerging from the earlier opening of the portal – why is this possible?
• Are other stories possible?
  

• What about our world according to general relativity? Maybe yes.
  

2. Are all initial states consistent with portals?

• Cellular automata:
• Life – see http://www.bitstorm.org/gameoflife/
  
• My life: 1D space – in the next generation, any cell will be …
  
• … occupied if 1 or 2 cells of the neighborhood are occupied presently.
• … unoccupied otherwise.
  

• Cellular automata example: No
• State (i) does evolve consistently, but …
  
• … state (ii) does not.
  

• What about our world according to general relativity? Maybe …