Energy indeterminacy

In thermodynamics, internal energy is the only form of energy that aligns with the concept of energy in other domains of physics. Internal energy is a conserved quantity governed by the first law of thermodynamics, but it is inherently indeterminant, meaning that we cannot determine its absolute value. This implies that it is nonsensical to discuss the amount of energy. We can only discuss changes or transfer of energy.

While internal energy is a conserved quantity, free energy, such as Helmholtz free energy is not. Helmholtz free energy represents the maximum work the system can perform under specific conditions. It is free energy that indicates the capacity to do work, yet free energy is not conserved because it accounts for dispersal due to entropy changes.

Understanding this distinction seems to be crucial: while energy is conserved, free energy is not subject to conservation laws.