This lecture begins with the instructor addressing feedback from students, expressing disappointment in the low response rate. The focus then shifts to explaining the importance of chaos theory in understanding turbulence, emphasizing the need to comprehend how deterministic equations generate chaos. The lecture delves into the derivation of Kolmogorov's fourth law, which links the third-order structure function to energy flux. The instructor highlights the significance of isotropy in simplifying the expression for energy flux in isotropic turbulence. The lecture concludes with a discussion on the assumptions and logic behind deriving Kolmogorov's fourth law, emphasizing the role of finite dissipation and the infinite Reynolds number limit in turbulent flow analysis.