> It's been almost 100 years since the initial clash between classic mechanics and quantum theory, and how much closer are we to unification?
There is no problem with, to use your words, unification of classical mechanics and quantum theory
Classical Mechanics is recovered from Quantum Mechanics in the limit of h-bar (Planck's constant) goes to zero. In our day to day experience, Planck's constant is so small as to effectively be zero. The non-intuitive effects of Quantum Mechanics occur when we probe areas where the non-zero value of Planck's constant cannot be ignored.
There has been enormous progress in the last 100+ years in understanding how the world is described by Quantum Theory. In some ways, the so-called Standard Model of Particle Physics can be seen as the crowning achievement of that work.
The only remaining question on that front is the absence of a testable theory that describe gravitation as a quantum theory. String Theory appears to be a leading candidate for this, but it has not, so far, made any testable prediction outside of what we already know from other theories.
There is no problem with, to use your words, unification of classical mechanics and quantum theory
Classical Mechanics is recovered from Quantum Mechanics in the limit of h-bar (Planck's constant) goes to zero. In our day to day experience, Planck's constant is so small as to effectively be zero. The non-intuitive effects of Quantum Mechanics occur when we probe areas where the non-zero value of Planck's constant cannot be ignored.
There has been enormous progress in the last 100+ years in understanding how the world is described by Quantum Theory. In some ways, the so-called Standard Model of Particle Physics can be seen as the crowning achievement of that work.
The only remaining question on that front is the absence of a testable theory that describe gravitation as a quantum theory. String Theory appears to be a leading candidate for this, but it has not, so far, made any testable prediction outside of what we already know from other theories.