Enthalpy represents the size difference between sensations felt on the left side vs the right side. The comparison is considered over all classes of sensation. To be more specific, let particle P be characterized by its quark coefficients and their associated internal energies . Recall that is an index that notes quark-type. The enthalpy of P is defined as

We also make use of a partial sum over just the chemical quarks that is written as

Enthalpy is conserved when compound quarks are formed or decomposed because it is defined by sums over quarks, and quarks are conserved.

## Enthalpy of Anti-Particles

The assumption of conjugate symmetry requires that the internal energy of ordinary-quarks and anti-quarks are the same as each other. We write . Also , the net number of quarks, in particle and its anti-particle , are related by

So the enthalpy of particles and their anti-particles are related as

## Sensory Interpretation of Enthalpy

The internal energy is defined from the specific energy of a particle. This specific energy represents the size of a perception. And quarks are objectified from thermal, visual, somatic and taste sensations. So a sensory interpretation of enthalpy is an awareness of size for all these kinds of sensations, net left-side from right. Next we use this notion of size to define the radius of a composite quark.