The number of people who identify themselves as atheists in the United States has been steadily rising in recent years. According to the Pew Research Center, when asked about their religious identity, 2.4 percent of Americans say they are atheists, up from 1.6 percent in 2007.

Here are nine things you should know about atheism:

1. Atheism is the belief that there is no God or gods. But because that belief can be held dogmatically or conditionally, some atheists refer to positive atheism (also called strong or hard atheism) and negative atheism (also called weak or soft atheism). The terms positive and negative atheism were popularized by the philosopher Anthony Flew (an atheist who became a deist):

Whereas nowadays the usual meaning of 'atheist' in English is 'someone who asserts that there is no such being as God', I want the word to be understood not positively but negatively. I want the originally Greek prefix 'a' to be read in the same way in 'atheist' as it customarily is read in such other Greco-English words as 'amoral', 'atypical', and 'asymmetrical'. In this interpretation an atheist becomes: not someone who positively asserts the non-existence of God; but someone who is simply not a theist. Let us, for future ready reference, introduce the labels 'positive atheist' for the former and 'negative atheist' for the latter.

2. In the West, atheism did not emerge into an unequivocally expressed belief system until the late Enlightenment. David Berman claims the first avowedly atheistic work was Baron d’Holbach’s The System of Nature published in 1782. Thereafter it became much more common to hear atheists admit their unbelief. For instance, by 1791 the Marquis de Sade wrote “There is no God. Nature sufficeth unto herself; in no wise hath she need of an author” and in his personal will said that he was “atheistic to the point of fanaticism.”

3. It was during the Enlightenment that the materialism espoused by most Western atheists began to be rebutted by theists and deists. For instance, in his Philosophical Dictionary on the entry “Atheism”, the French philosopher Voltaire, wrote:

We are intelligent beings: intelligent beings cannot have been formed by a crude, blind, insensible being: there is certainly some difference between the ideas of Newton and the dung of a mule. Newton's intelligence, therefore, came from another intelligence.

When we see a beautiful machine, we say that there is a good engineer, and that this engineer has excellent judgment. The world is assuredly an admirable machine; therefore there is in the world an admirable intelligence, wherever it may be. This argument is old, and none the worse for that.

4. In 1967 Albania officially became the first atheistic state. As Finngeir Hiorth writes, “On 22 November 1967, the government published a decree which annulled the religious charters and all laws pertaining to state-church relationships. All religious rites were prohibited, and grave penalties were imposed on violators. The few remaining priests were sent to forced-labor camps for 're-education.' At this time the constitution still guaranteed freedom of conscience and religion. But this was changed in 1976 when all religious organizations became illegal according to the constitution.”

5. The countries with the highest percentage of citizens who say they are “convinced atheists” are China (47 percent), Japan (31 percent), Czech Republic (30 percent), France (29 percent), South Korea (15 percent), Germany (15 percent), Netherlands (14 percent), Austria, Iceland, Australia, and Ireland (all four with 10 percent).

6. Atheism is recognized as equivalent to a 'religion' for purposes of the First Amendment. (See, for example, Supreme Court case Wallace v. Jaffree). The case of Reed v. Great Lakes Cos also made clear that atheist cannot be fired from a job because of their “religious beliefs”: “If we think of religion as taking a position on divinity, then atheism is indeed a form of religion.”

7. Atheists in America are more likely to be male and younger than the overall population: 67 percent are men, and 38 percent are ages 18-29 (compared with 22 percent of all U.S. adults).

8. A quarter (26 percent) of self-professed atheists say they think of themselves as spiritual people, and 3 percent consider themselves religious people. Four-in-ten atheists (41 percent) say they often think about the meaning and purpose of life.

9. Many people in American who claim to be atheist don’t fit the conventional definition; conversely, many who do choose not to self-identify as atheist. Of those who call themselves atheists, 14 percent also say they believe in God or a universal spirit (including 5 percent who say they are “absolutely certain” about the existence of God or a universal spirit). More Americans say they do not believe in God or a universal spirit (7 percent) than say they are atheists (2.4 percent).

Other posts in this series:

Intimate Partner Violence • Rabbinic Judaism • Hamas • Male Body Image Issues • Mormonism • Islam • Independence Day and the Declaration of Independence • Anglicanism • Transgenderism • Southern Baptist Convention • Surrogacy • John Calvin • TGC • Prayer in the Bible • The Rwandan Genocide • The Chronicles of Narnia • The Story of Noah • Fred Phelps and Westboro Baptist Church • Pimps and Sex Traffickers • Marriage in America • Black History Month • The Holocaust • Roe v. Wade • Poverty in America • Christmas • The Hobbit • Council of Trent • C.S. Lewis • Orphans • Halloween and Reformation Day • Down Syndrome •World Hunger • Casinos and Gambling • Prison Rape • 6th Street Baptist Church Bombing • 9/11 Attack Aftermath • Chemical Weapons • March on Washington • Duck Dynasty • Child Brides • Human Trafficking • Scopes Monkey Trial • Social Media • Supreme Court's Same-Sex Marriage Cases • The Bible • Human Cloning • Pornography and the Brain • Planned Parenthood • Boston Marathon Bombing • Female Body Image Issues