  One distinctive and pervasive aspect of social systems is the fact that they
comprise several kinds of agents. Thus, in order to draw parallels with
physical systems one is lead to consider binary (or multi-component) compounds.
Recent views about the mixing of liquids in solutions gained from neutron and
X-ray scattering show these systems to have a number of similarities with
socio-economic systems. It appears that such phenomena as rearrangement of
bonds in a solution, gas condensation, selective evaporation of molecules can
be transposed in a natural way to socio-economic phenomena. These connections
provide a novel perspective for looking at social systems which we illustrate
through some examples. For instance, we interpret suicide as an escape
phenomenon and in order to test that interpretation we consider social systems
characterized by very low levels of social interaction. For those systems
suicide rates are found to be 10 to 100 times higher than in the general
population. Another interesting parallel concerns the phase transition which
occurs when locusts gather together to form swarms which may contain several
billion insects. What hinders the thorough investigation of such cases from the
standpoint of collective phenomena that we advocate is the lack or inadequacy
of statistical data for, up to now, they were collected for completely
different purposes. Most essential for further progress are statistics which
would permit to estimate the strength of social ties and interactions. Once
adequate data become available, rapid advance may be expected.
