I have had numerous conversations with non-Christians where the truth of Christianity is dismissed by pointing out its diversity. The charge usually goes something like this: “How can you argue for what is true when you Christians can’t even agree amongst yourselves?” Below is a recent answer I offered for this objection to someone claiming that there were “40,000 Christian sects.”
It should first be pointed out what a “sect” actually is. Applied to Christianity, a “sect” is different than a “denomination.” Denominations share essential beliefs, but differ in non-essentials (e.g., Methodist, Baptist, Presbyterian, Lutheran). In general, they hold the other denominations to be legitimate expressions of Christianity, and the differences are due to ecclesiastical preferences or conclusions on things not explicitly covered in Scripture. A sect is a group that tends also to share most essential beliefs, but adds some distinctives that they think essential and/or think of themselves as the pure church (e.g., Seventh Day Adventists). Additionally, there are “cults.” These are groups that deny one or more essentials held by all these other groups, usually due to the teachings of some “prophetic” leader, and who usually think of themselves as the true, restored church where others have gone critically astray (e.g., Mormons, Jehovah’s Witnesses, Christian Science).