Q: I was surprised to learn that a deist believes one God created the universe but otherwise ignores it, whereas a theist believes one God created the universe and actively intervenes in it. Do you know how this distinction came about?
A: I’ve always considered a deist to be someone who believes in God but not in any particular religion. The Oxford English Dictionary generally agrees with me, but two of the other dictionaries I often consult go along with your definition.
The OED says a deist is someone “who acknowledges the existence of a God upon the testimony of reason, but rejects revealed religion.”
The American Heritage Dictionary of the English Language (4th ed.) says deism is a “belief, based solely on reason, in a God who created the universe and then abandoned it, assuming no control over life, exerting no influence on natural phenomena, and giving no supernatural revelation.”
Merriam-Webster’s Collegiate Dictionary (11th edition) says deism is “a movement or system of thought advocating natural religion, emphasizing morality, and in the 18th century denying the interference of the Creator with the laws of the universe.”
As for a theist, the three dictionaries generally define it as someone who believes in God and who may or may not follow a particular religion.
The terms “deist” and “theist” meant pretty much the same thing (the opposite of “atheist”) when they first showed up in English (“deist” in the 16th century and “theist” in the 17th century), according to the OED.
The dictionary says the two words were “interchangeable” at the end of the 17th century. But by the late 18th century, according to published references, the term “deist” had come to mean someone who believed in God, but not in the Scriptures.
In 1788, for instance, the Anglican theologian John Wesley defined a “deist” as “one who believes there is a God distinct from matter; but does not believe the Bible.”
In the late 19th century, according the OED, a “negative aspect of deism, as opposed to Christianity, became the accepted one, and deist and theist were differentiated.”
Here’s an 1880 citation from the Saturday Review: “In speaking of a deist they fix their attention on the negative, in speaking of a theist on the positive aspect of his belief.”