Atheism is a non-theistic philosophical theory of reality that essentially has two definitions. The basic premise is that there is no god. In addition, there exists a concept denying the necessity of a creator. The theory holds that the world could easily exist scientifically and human reality is based on the human experience. An alternate meaning for atheism denies belief in supreme beings of any type. General cause and effect principles of physics suggest that reality was initiated by a displacing force; the original energy was not a conscious, supernatural being.
The contemporary translation of the term stems from the Greek altheas, or "godless," but is actually derived from the French word atheisme. Though the terminology of atheism began as early as the 16th Century, it actually did not appear as a philosophy until the 18th century. The theory is the natural antithesis to Christianity and Islam, but is a significant component of Buddhism, Jainism and Hinduism. Accusing someone of being an atheist was traditionally derogatory in Western civilization until contemporary religious tolerance emerged.
Atheism can easily be considered a mercurial theory. Many atheists doubt the need for existence of the word and consider it an indignant description of an individual for an inaction or non-conviction, that the term alone suggests that all rational beings are required to have a belief system that includes a deity. Atheism argues that a deity is not necessary just as the label is not necessary. Atheism is effectively an advancement of the Aristotelian concept of existence as being and promotes the idea of the "blank slate," meaning that no one is born with an a priori concept of God. Everyone is a product of their particular environment and individual experiences. Concepts of deity are taught by external beings.
In Europe during the Enlightenment, the stigma of atheism was applied to several of the great philosophers of the time. Hume and Hobbes were both attacked for unconventional religious conviction but were able to defend themselves literally. John Locke, creator of the concept of libertarianism, would only espouse tolerance between the separate Christian sects. Locke's writings were the basis for the general religious tolerance supposedly established in the United States.
According to Locke, separation of Church and State and emphasis on individualism were necessarily entangled ideas. He stopped short of condoning freedom of thought, suggesting only freedom of worship. It is generally accepted that Locke was an atheist who understood negative politics. Spinoza's theory of "pantheism" was also considered to be atheistic, though it is actually a polytheistic religion. It was obvious that control of the masses included the control of spiritual thought.
General irreligion was also prevalent in Europe during this time, as many were still uneducated and unconcerned. Theism lacked empirical evidence and this was even apparent to the general populace. Profession of atheism was considered criminal in many societies for centuries, so the claim and discussion of the theory was chilled. With the Enlightenment came the return to individual thought and the re-evaluation of the concept of original sin. Those who were literate and affected by the re-emergence of the theories of the Classical Greek thinkers returned to the initial Aristotelian/Platonist split of being vs. becoming. The philosophical split occurred directly following the death conviction of Socrates for the charge of "impiety" for promoting the idea of the psyche, or the soul.
Contemporary views of atheism are clearly more acceptable of the concept of a godless universe. The rise of socialist theories of the 19th and 20th Century opened the dialogue as entire countries were claiming atheism as a political predisposition and atheistic theory was allowed to be discussed with limited interference. This has given rise to the more recent concept of Secular Humanism, which denounces the mischaracterization of atheism as leading to lawlessness and a lack of moral character. The exclusionary assumptions and misperceived attacks by theists upon atheists and atheism itself have been largely challenged by science and the fact that technology advancement still has yet to provide empirical evidence of the actual existence of a supreme deity.