I see three main divisions/definitions of secularism.
- Political
- Philosophical
- Social
Political Secularism: The separation of church and state is the foundation of political secularism. This is to protect the rights of believers of all faiths, and the rights of non believers. It keeps the church out of government business and the keeps government out of church business.
Philosophical Secularism: This is the body of study which seeks to critique religions and prove them wrong. This is often referred to as New Atheism promoted by writers like Richard Dawkins.
Social Secularism: This is the idea of that religiosity will weaken over time as the population gets more educated.