Wherever any performance or forbearance are not equally in a man's power; wherever doing or not doing will not equally FOLLOW upon the preference of his mind directing it, there he is not free, though perhaps the action may be voluntary.

So that the idea of LIBERTY is, the idea of a power in any agent to do or forbear any particular action, according to the determination or thought of the mind, whereby either of them is preferred to the other: where either of them is not in the power of the agent to be produced by him according to his volition, there he is not at liberty; that agent is under NECESSITY.

So that liberty cannot be where there is no thought, no volition, no will; but there may be thought, there may be will, there may be volition, where there is no liberty.

A little consideration of an obvious instance or two may make this clear.
9.

Supposes Understanding and Will.
A tennis-ball, whether in motion by the stroke of a racket, or lying still at rest, is not by any one taken to be a free agent.