The active and passive conditions of movement do not necessarily exist in a mutually exclusive state. A movement may engage in the attributes of both active and passive conditions.
If I am lifting a heavy weight and a second person assists me, I am both actively and passively engaged in the movement.

1. Actively, to the extent that I myself am doing the work,
2. Passively, to the extent that the assistance offered relieves me of the necessity for doing it all.

The degrees to which the two forms combine are unlimited, varying throughout the entire dynamic range of movement. The assistance which we receive may be almost nothing, when the movement will be almost entirely active. Or the assistance may be nearly complete, in which case the movement will be practically entirely passive.

The question remains as to how gravity, as an external force, affects the activity and passivity of movement . The arm, unless supported by some external resistance or muscular contraction, will fall through the action of gravity. Hence, without the contraction of the arm-depressors.
Question: Is this, then a passive movement?
We shall be obliged to answer yes, because our definition of passivity was based upon absence of muscular contraction. When, however, such an arm-drop is controlled, and the uncontrolled drop plays no part in piano technique, we have at least a partially active movement.
Moreover, since gravity is a constant, and a force actually determining the basic coordination of all physiological movements, we may safely exclude it as a determinant of the activity or passivity of a movement in the sense in which the variable external resistance introduced by some obstacle or second person acts as a determinant.
This does not mean, however, that its influence on the various touch-forms is to be minimized.
Quite the contrary, its action is certainly one of the important determinants, perhaps the most important, of the forms of movement used in all piano touches. In order to avoid confusion of terms, I shall discuss this action under the

1. positive and
2. negative

aspects of the various touch-forms.