First Law: It is impossible to obtain something from nothing, but one may break even
Second Law: One may break even but only at the lowest possible temperature
Third Law: One cannot reach the lowest possible temperature
Implication: It is impossible to obtain something from nothing, so one must optimise resources
-- Kalyan Annamalai & Ishwar K. Puri, Advanced Thermodynamics Engineering, CRC Series in COMPUTATIONAL MECHANICS and APPLIED ANALYSIS, 2002
\Delta I <= k_B T \ln 2
The skeleton of entropy relentlessly advances forward, bearing the sword of dissolution but also the arrow of time.
Entropy is the root of all decay. It turns books to dust, heat to cold and life to death. It always increases, moving us towards the heat death of the universe. It doesn’t promise change or transformation, just stable states of maximal uninterestingness. It is impossible to escape because it is so fundamental: as long as unlikely states randomly move towards likely states entropy will win.
And yet it is the driver of change. Without irreversibility time would not have any direction. Objects would decay and undecay. Evolution would cease, as selection would no longer remove unfit genomes: individuals would die and un-die randomly. The thinking process moving from ignorance towards knowledge would be as likely as moving from knowledge to ignorance. Life depends on the dissipation of energy to preserve its low entropy, its identity. Without entropy life would become arbitrary.
Yet we do not welcome entropy. It is the foe that never sleeps, and as living beings we are fighting an uphill struggle against it. We must, because to give in is to cease life. Being metastable states random chance will eventually get us. But we can reproduce, protect ourselves, make backups and make the risks as small as possible. Immortality is not precluded, just easy immortality.
Death. Decay. Irreversible acts and decisions. One-way directions. Cold. You cannot beat the house.