  A system of two interacting protofields with generic parameters is unstable
with respect to unceasing cycles of nonlinear squeeze (reduction) to randomly
chosen centres and reverse extension which form the causally probabilistic
process of quantum beat observed as elementary particle (quant-ph/9902015).
Here we show that the emerging wave-particle duality, space, and time lead to
the equations of special relativity and quantum mechanics thus providing their
causal extension and unification. Relativistic inertial mass (energy) is
universally defined as the temporal rate (frequency) of the chaotic quantum
beat process(es). The same complex dynamical processes and mass account for
universal gravitation, since any reduction event in the electromagnetic
protofield involves also the (directly unobservable) gravitational protofield
thus increasing its tension and influencing quantum beat frequencies of other
particles. This complex dynamical mechanism of universal gravitation provides
causal extension of general relativity intrinsically unified with causal
quantum mechanics and special relativity, as well as physical origin and
unification of all the four 'fundamental forces' (also gr-qc/9906077). The
dynamic origin of the Dirac quantization rules is also revealed and used for
the first-principles derivation of the Dirac and Schroedinger equations
describing the same irreducibly complex, internally nonlinear interaction
processes within field-particles and their simplest systems (quant-ph/9511034 -
quant-ph/9511038). The classical, dynamically localised behaviour naturally
emerges as a higher level of complexity appearing as formation of elementary
bound systems (like atoms).
