What did George Berkeley mean by spirit?

For the Irish philosopher George Berkeley, the term spirit refers to a "simple, undivided, active being," which he identifies as a mind or soul.1

In his philosophical framework, Berkeley distinguishes between two entirely distinct categories of existence:
* Active spirits: These are beings capable of perceiving, thinking, and willing. The activity of a spirit consists of two primary functions: understanding (perceiving ideas) and will (producing ideas).21
* Passive objects: These are sensible ideas or sense-data, which exist only insofar as they are perceived by a spirit.21

Unlike physical objects, which are collections of ideas that depend on a perceiver for their existence, spirits are the active agents that perform the perceiving. Berkeley argued that because no idea can exist outside of a mind, the continued existence of the physical world—even when not perceived by humans—is maintained by the mind of God, who is the ultimate spirit.21