le pli p. 129
1) Leibniz doesn't say that perception resembles an object, but that perception evokes a vibration, which is gathered by an organ receptor.
2) Even if the perceived resembles something, it does not immediately follow that perception represents an object. The perceived and perception do not resemble what is understood nor the movement of an object, but the matter in what is understood; in other words the vibrations, springs, "tendances or efforts" in movement.
3) The particularity of an organ receptor is that it contracts the vibration which it receives. The receptor is at the origin of a principle of physical causality, since it gathers the effect of an infinity of causes.