The Mental, the Mind and the Body

I would like to give an account of the mental, the
mind and the body.
To begin, let us consider some of the differences
between objects and activities. An object has spatial
extension and can exist at an instant of time. Objects are
considered to have properties whose spatio-temporal
conjunction is commonly thought to define what the object
is. No temporal extension seems to be necessary for the
object to be what it is. The object can exist at an instant.
Similarly, the object can remain through time what it is,
without changing any of the properties commonly thought
to be internal to it.
In contrast, an activity does not have spatial
extension at an instant, though the object performing the
activity does. Yet the activity necessarily has temporal
extension. There is no activity at an instant. As a
consequent, the continuance of the activity through time
requires continuance in the change that is the activity.