  Life occurs in ionic solutions, not pure water. The ionic mixtures of these
solutions are very different from water and have dramatic effects on the cells
and molecules of biological systems, yet theories and simulations cannot
calculate their properties. I suggest the reason is that existing theories stem
from the classical theory of ideal or simple gases in which (to a first
approximation) atoms do not interact. Even the law of mass action describes
reactants as if they were ideal. I propose that theories of ionic solutions
should start with the theory of complex fluids because that theory is designed
to deal with interactions from the beginning. The variational theory of complex
fluids is particularly well suited to describe mixtures like the solutions in
and outside biological cells. When a component or force is added to a solution,
the theory derives - by mathematics alone - a set of partial differential
equations that captures the resulting interactions self-consistently. Such a
theory has been implemented and shown to be computable in biologically relevant
systems but it has not yet been thoroughly tested in equilibrium or flow.
