  The remarkable connections between gravity and thermodynamics seem to imply
that gravity is not fundamental but emergent, and in particular, as Verlinde
suggested, gravity is probably an entropic force. In this paper, we will argue
that the idea of gravity as an entropic force is debatable. It is shown that
there is no convincing analogy between gravity and entropic force in Verlinde's
example. Neither holographic screen nor test particle satisfies all
requirements for the existence of entropic force in a thermodynamics system.
Furthermore, we show that the entropy increase of the screen is not caused by
its statistical tendency to increase entropy as required by the existence of
entropic force, but in fact caused by gravity. Therefore, Verlinde's argument
for the entropic origin of gravity is problematic. In addition, we argue that
the existence of a minimum size of spacetime, together with the Heisenberg
uncertainty principle in quantum theory, may imply the fundamental existence of
gravity as a geometric property of spacetime. This may provide a further
support for the conclusion that gravity is not an entropic force.
