Metaphysics

Metaphysics encompasses a wide range of general and abstract topics. It investigates the nature of existence, the features all entities have in common, and their division into categories of being. Modal metaphysics examines what it means for something to be possible or necessary. 

An influential division is between particulars and universals. Particulars are individual unique entities, like a specific apple. Universals are general features that different particulars have in common, like the color red. 

Metaphysics also explores the concepts of space, time and change and their connection to causality along with the laws of nature. Other topics include how mind and matter are related, whether everything in the universe is predetermined, and whether there is free will.