  String Theory is the result of the conjunction of three conceptually
independent elements: (i) the metaphysical idea of a nomological unity of the
forces, (ii) the model-theoretical paradigm of Quantum Field Theory, and (iii)
the conflict resulting from classical gravity in a quantum world. String Theory
is sometimes assumed to solve this conflict: by means of an application of the
model-theoretical apparatus of (perturbative) Quantum Field Theory. But, String
Theory does not really solve the conflict. Rather it exemplifies the inadequacy
of this model-theoretical apparatus in the context of Quantum Gravity: After
several decades of development it still exists only in an essentially
perturbative formulation (with minor non-perturbative extensions and vague
ideas with regard to a possible non-perturbative formulation). And, due to its
quantum field theoretical heritage, it is conceptually incompatible with
central implications of General Relativity, especially those resulting from the
general relativistic relation between gravity and spacetime. All known
formulations of String Theory are background-dependent. On the other hand, it
was not even possible to reproduce the Standard Model. Instead, String Theory
led to a multitude of internal problems - and to the plethora of low-energy
scenarios with different nomologies and symmetries, known as the String
Landscape. All attempts to find a dynamically motivated selection principle
remained without success, leaving String Theory without any predictive power.
The nomological unification of the fundamental forces is only achieved in a
purely formal way within the model-theoretical paradigm of Quantum Field Theory
- by means of physically unmotivated epicycles like higher dimensionality,
Calabi-Yau spaces, branes, etc.
