1. Gravity field equations can be derived from the thermodynamic relation for any metric theory of gravity Merav Hadad Ram Brustein, M.H. 0903.0823

2. T - Unruh temperature Einstein equations can be derived from the thermodynamic relation (Jacobson,’95) (Raychauduri equation)

3. the equation of motion can be derived from the thermodynamic relation if the entropy is a Noether charge entropy. (E. Elizalde & P. Silva, 2008) Ricci scalar theories

4. Any effective action We have generalized Jacobson's derivation to any theory of gravity keeping the volume fixed during variation

5. The energy measured by the observer Integration over a short segment of a thin pencil of horizon generators a (D−1) volume form In agreement with Jacobson

6. The entropy in generalized theories of gravity with bifurcate Killing horizon bi-normal vector to the area element (D-2) volume form The entropy variation

7. Gravity field equations for any theory of gravity.

8. We have generalized Jacobson's derivation to any general theory of gravity. Are all the gravitation equations actually a macroscopic description of an underlying microscopic dynamical system ?