Atheism (pure) - Complete rejection of the possibility for the existence of conscious ethereal beings or concepts (gods, spirits or spirituality, afterlife, reincarnation, etc.)

Agnosticism - A lack of choosing between being an atheist or a believer. Agnosticism is in itself not a perspective, it is merely the absence of a firm commitment to either atheism or a faith because it's assumed that the existence of a god cannot be proven or disproven

Freethinker - One who thinks independently of authority or dogma, instead choosing logic and rationality to pursue knowledge

Humanism - Subclass of atheism that focuses on human needs and improvement

Materialism - Purports all that exists must be physically tangible material, or the effects upon said material

Objectivism - Similar to Materialism. All reality is objective and external to our minds, and our knowledge of reality can be deemed reliable based upon observations

Scientific - The strict preclusion of human emotional bias in measuring/assessing (the value of) information. Defines methods for evaluating the credibility of information

Rationalism - Logic is the primary source of knowledge

Libertarianism - Advocating free will while minimizing state intervention