What changes, when made to string theory, change it into a predictive, falsifiable theory?

1. After writing down the action principle and obtaining the equations of motion, one must not quantise the dynamics. The theory is already pre-quantum and pre-spacetime, and gravitation, and quantum theory, are emergent in a statistical thermodynamics approximation.

2. One must not assume the Minkowski vacuum to be the ground state of quantum gravity, and construct a Fock space over it. Just as the ground state of a harmonic oscillator has a non-vanishing wave function, and a non-vanishing zero point energy, it can be expected that the average Riemann curvature will be non-zero in the quantum gravitational ground state.

3. It has been found that when elementary particles are defined as excitations of the algebraic vacuum in the octonion algebra [idempotent / projector] then one makes immediate contact with the standard model and with Lorentz symmetry. There is a procedure for calculating the free parameters of the standard model.

Thus, if we do not quantise the string theory Lagrangian, but take it as a pre-quantum Lagrangian dynamics, and develop string theory on an octonionic space, the theory becomes predictive and falsifiable. The derivation of the fine structure constant and mass ratios could as well be called results of a resurrected string theory

Reference:

Quantum Theory without Classical Time: a route to quantum gravity and unification

https://arxiv.org/abs/2110.02062