Definition

1. Noun:
   • The primary source of motion or change; the first cause: In medieval philosophy and cosmology, the "primum mobile" refers to the outermost celestial sphere, believed to be the first moved by God and which imparts motion to all the inner spheres. By extension, it denotes the ultimate, uncaused cause or prime mover of all things.

Usage Examples

• Noun:
  • In Ptolemaic astronomy, the primum mobile was thought to be the sphere that drove the daily motion of the heavens.
  • Philosophers have long debated the nature of the primum mobile, the uncaused first cause of the universe.

Advanced Usage

• As a conceptual metaphor: Used to describe the fundamental driving force or primary instigator behind a complex system or series of events.
  • In his analysis of the economic crisis, he identified speculative banking as the primum mobile of the collapse.

Variants and Related Words

• Prime mover (n): A synonym often used in philosophy and theology for the first cause or initial source of motion.
  • Aristotle's concept of the unmoved mover is a philosophical precursor to the idea of the primum mobile.
• First cause (n): The initial, self-caused agent that begins a chain of causation.

Synonyms

• Prime mover
• First cause
• Primary agent
• Original source

Related Phrases and Idioms

• The unmoved mover: A related Aristotelian philosophical concept denoting a cause that is itself uncaused.
• To set/put something in motion: While not containing the target phrase, this idiom relates to the concept of being an initial cause or instigator.

Noun

1. an agent that is the cause of all things but does not itself have a cause
   • God is the first cause