  In their constructions of system of quantum stochastic differential
equations, mathematicians and/or several physicists interpret that the function
of random force operator is to preserve the canonical commutation relation in
time, i.e., to secure the unitarity of time evolution generator even for
dissipative systems. If this is the case, it means physically that the origin
of dissipation is attributed to quantum non-commutativity ({\it quantumness}).
The mechanism that the mathematician's approaches rest on will be investigated
from the unified view point of Non-Equilibrium Thermo Field Dynamics (NETFD)
which is a canonical operator formalism of quantum systems in
far-from-equilibrium state including the system of quantum {\it stochastic}
equations.
