Nondualism

Nondualism is an extremely broad and profound philosophical concept which includes Monism as it's sub-ideology. Nondualism - despite it accepting two or more universal principles that are unique to each other - argues that they are simultaneously complementing each other and even cannot exist without each other. For example, Nondualism argues that the self (subject) and the universe (object) - despite being seemingly different - are actually ultimately the same thing.