I have gotten many answers, and coupled with most responses is an acknowledgment of the difficulty of the endeavor. Buddhism is a huge topic, awash in a jargon whose impenetrable status drops farther and farther from mind with each attended retreat.
I’ve seen Buddhism described in opposition to other religions, stressing the non-godliness of the Buddha and the rationality its teachings, but this seems to be not stating Buddhism on its own terms. I’ve seen explanations grounded in the Buddha’s life which do a great job of framing the concerns of Buddhism, but can make Buddhism seem less immediate and relevant. I’ve seen and attempted personal appeals, drawing out the differences and benefits measured in my own life. This approach is only effective for people who are willing to listen to me describe the intense Buddhist significance of giving up potatoes.
Of course, people have been answering this question since the time of the Buddha, in one form or another. My favorite are historical accounts of interactions with Buddhists; because they answer a related but slightly different question: How does a non-Buddhist talk to people about Buddhism for the first time? What are the most pertinent details.
The following is from the Weilu a third-century history text that has been lost and currently exists only in fragments found in The History of the Three Kingdoms and a few other places. The translation is by John H. Hill, available online from the University of Washington:
Regarding the kingdom of Lumbini, the Buddhist books say:
“The king of this country fathered the Buddha. The Buddha was the heir apparent. His father was called Suddhodana. His mother was called Maya.
The Buddha wore yellow clothes. His hair was silky black. The hair on his chest was black; his complexion a coppery-red.
Initially Maya dreamed of a white elephant and became pregnant. When the Buddha was born, he emerged from the left side of his mother. At his birth, he had a topknot of hair. As soon as he touched ground, he was able to take seven steps.”
This kingdom is in the centre of the towns of Tianzhu (Northern India). Also, there was another holy man named Sāriputra in Tianzhu.
Previously, in the first Yuanshou year (2 BCE), during the reign of Emperor Ai of the Han dynasty, the National University Student, Jing Lu, received verbal instructions from Yicun, the envoy of the king of the Kushans, on the Buddhist sūtras which say this man is the one who is reincarnated.
The Buddhists mention linpusai, sangmen, bowen, shuwen, baishuwen, biqiu, chenmen, which are all terms for disciples.
The Buddha’s [teachings] are related to, but different than, the scriptures of Lao Zi of the Middle Kingdom (China). Indeed, it is believed that Lao Zi left the passes and, heading west, crossed the Western Regions to Tianzhu, where he taught the Westerners.
There are, altogether, twenty-nine titles for disciples of the Buddha, which I am not able to give in detail, so I have summarised them as above.
The decisions made in the Weilu are interesting ones. The passage begins with an outline of the Buddha’s life, including a description of the Buddha’s appearance. This would suggest that the readers would either be unfamiliar with Buddha images, or that there was an acknowledgment that the Buddha’s appearance varied from his common religious depictions.
The mention of oral transmission to a particular Chinese scholar (who is of no other historical significance) is used by some to date the earliest written account of a Chinese Buddhist (2 BCE), predating legendary arrival of the first Buddhist monks during the Reign of Emperor Ming of the Han dynasty (r. 57-75 CE).
The text also features a gem that may be unfamiliar to many readers: the assertion that Laozi taught the Buddha. Later formalized in the Huahu Jing, it is presented here first in all of its ridiculous glory. The most blaring omission is of course any basic details of the Dharma, as well as descriptions of Buddhist life or the life of monastics; presumably glossed by the association with Daoism.
And in regards to this last detail, perhaps our modern first descriptions of Buddhism are not too different, for all the times that Buddhism becomes the “eastern psychology,” “eastern transcendentalism,” or other varieties of feel good crystal rubbing thought patterns.
Splendid photo of Ming dynasty texts taken by Gisling and used under Creative Commons.