Why We Need Different Approaches

Why we need different approaches?

graph TB A[Why we need different approaches?] B[Classical Physics] C[Quantum Physics] D[Relativity Theory] E[Statistical Mechanics] F[Field Theory] A --> B A --> C A --> D A --> E A --> F B --> G[Newton's Laws] C --> H[Wave-Particle Duality] D --> I[Space-Time Curvature] E --> J[Entropy and Probability] F --> K[Quantum Fields]