Entropic Force and Gravitation

In this post, I offer a (hopefully) user-friendly conceptual introduction to gravitation as an entropic force, from the perspective of the transactional formulation. This account departs somewhat from traditional presentations of entropic gravity and the holographic principle by insisting that “information” alone is not physically sufficient to define thermodynamic entropy. Entropy must always be defined by reference to energy and temperature, and has nothing to do with anyone’s knowledge or lack thereof. We can clearly replace “information” by entropy in the transactional formulation because it makes clear how energy is always involved in establishing measurement results, which are the relevant forms of “information” for thermodynamic purposes.