Statistical Mechanics

Statistical Mechanics #

Origins: Thermodynamics #

• Second Law of Thermodynamics: Entropy is unlikely to decrease over time
  • Systems tend toward states of high entropy

Main idea: the micro-physical explanation #

• macro-state = observable state of a system
• micro-state = microscopic, exact particles that comprise a system

There are many possible micro-states that result in a given macro-state.

It is very likely that any micro-state tends towards a higher entropy macro-state.

• macro-state never decreases entropy because vast majority of micro-states tend towards that

Implication: Universe tending towards state of equilibrium in the long run #

• Possible that universe will last infinitely long
• For most of the universe’s existence, it will therefore be in equilibrium
• Micro-states might cause momentary deviations (small chance): Boltzmann Brains
  • Highly unlikely, but probable if infinite universe

Boltzmann Brains #

Creation of momentary, isolated brains with exact memories + thoughts of a human. The brain’s experiences are entirely false.

Conclusion: It is overwhelmingly likely that our thoughts are false and therefore cannot be trusted. (It is unlikely that we are actually in our perceived environments.)