There's a reason that social media sites are filled with quotes, and why people often share clever memes. It's the same reason why inspirational quotes are often found in office cubicles and why organizations have mottos. In short: Quotes connect people, and people like to hear their own beliefs told to them in a clever way.

Most memorable quotes are short, pithy sayings that are easily memorized and repeated. The human brain is quite good at remembering clever turns of phrase or brief sound bites, and many famous quotations capitalize on this. Since they're so easy to remember, it's easy to repeat them later to people who will appreciate them.

Moreover, quotes serve as a way to connect people. If two people are familiar with a particular quote, they have common ground that can help spark more conversation. Similarly, people may be less willing to accept a particular viewpoint if it's coming from a stranger; if a valid argument is made by a person they recognize and trust, they'll be more likely to listen carefully.

Perhaps the greatest value of quotes, however, is their ability to encapsulate complex thoughts. It can be challenging to verbalize thoughts, believes and emotions, and even more difficult to do so in a way that others will find interesting or understandable. By borrowing another's famous words, people can express themselves more clearly.

Just as atheism is a general term that can encompass a wide variety of people, quotes for and about atheists can come in a variety of kinds. Here are just a few:

• Activist quotes discussing the need for equality, the rights of atheists or other related political topics: "As an atheist, I see nothing ‘wrong’ in believing in a god. I don’t think there is a god, but belief in him does no harm. If it helps you in any way, then that’s fine with me. It’s when belief starts infringing on other people’s rights when it worries me." -- Ricky Gervais
• Quotes criticizing religion, either in a serious or humorous manner: “Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?” -- Douglas Adams
• Humorous quotes poking fun at atheism in a way other atheists can appreciate: “Atheism is a non-prophet organization.” -- George Carlin
• Pithy statements that strike at the core of an issue in a way that's easy to recall later: “Those who can make you believe absurdities, can make you commit atrocities.” -- Voltaire
• Sound bites from famous writings that encapsulate the overall message of the speaker: “Human decency is not derived from religion. It precedes it.” -- Christopher Hitchens

There are many more types of quotes you may come across. Whether they're humorous, inspiring or simply thought-provoking, quotations can serve as a valuable starting point for any kind of conversation.

They can also serve as silent reminders of what you care about and how many other people in the world feel the same way.

The next time you find a quote that you find to be particularly appealing, consider sharing it with those whose opinions you value. You might be surprised at the thoughtful quality of conversation that follows. If nothing else, you should have a better idea of what the people around you actually think and believe, which can be extremely valuable.