Metaphysics

Metaphysics is a sub-field of philosophy that examines the nature of reality including relationships between the mind and matter. It can also deal with cosmology.

Kiri-kin-tha's first law of metaphysics states "Nothing unreal exists."

Emory Erickson, inventor of the transporter, denounced questioning if the person who arrived after a transport was the same person who left as "metaphysical chatter."

In 2266, Captain Kirk of the USS Enterprise (NCC-1701) engaged the supercomputer Landru in a metaphysical debate. Landru regarded itself as an exact copy of its maker, an ancient philosopher and engineer. Kirk exploited certain key differences between the creator and the created to set up a paradox that the machine could not resolve. These limitations, rooted in its understanding of the world and of itself, had prevented it from realizing the harm it was doing to the citizens of Beta III, in direct violation of its programming. They also prevented it from deducing a way to resolve that harm, and ultimately, it experienced catastrophic failure. 

In 2364, when the USS Enterprise (NCC-1701-D) crew were infected with polywater intoxication, the training division ordered officers to attend a lecture in metaphysics. 

Captain Phillipa Louvois felt that determining the nature of Data was a case of metaphysics. 

In 2366, Data included information on metaphysics in the "education" of his offspring Lal. . Data also considered the interpretation of visions a metaphysical matter.