51. What is the author’s purpose in writing these two passages?
(A) To explain what post hoc fallacy is.
(B) To support the conceptual basis for post hoc fallacy.
(C) To share stories about post hoc fallacy.
(D) To explore the origins of post hoc fallacy.

Many human superstitions start with this fallacy. A baseball player wears uncomfortable underwear while hitting a grand slam. From then on, that same tight, hole-pocked pair of underpants becomes part of his uniform. The fallacy has a fancy name: it’s a post hoc fallacy, from the Latin post hoc ergo propter hoc, which means “after this, therefore because of this.” People commit this fallacy when they think that a correlation - one thing happening with something else - is a cause. Some parents resist getting life-saving vaccinations for their two-year-olds because some kids get diagnosed with autism soon after they get their shots. Autism is detectable just about the same age that kids get their two-year vaccinations. That leads a few parents to think that vaccinations cause autism, even though science has clearly proven they don’t. 

The post hoc fallacy tends to hit us in subtle ways. A student parties all night and aces an exam. Conclusion: Partying strengthens his mental faculties! Never mind that he was paying extra attention in class and had already read the material thoroughly. Or you go on holiday and it rains the entire week. “I’m sorry,” you say to the hotel manager. “I made it rain.” Even if you were slightly kidding, you were committing an easy fallacy. If, however, you really did make it rain, you should switch careers. Farmers would pay you good money. (modified from Heinrichs, 2018)

*superstitions 迷信
excessively credulous belief in and reverence for the supernatural
*fallacy 謬論
a mistaken belief, especially one based on unsound arguments
*post hoc 事後的
made or happening only after an event, not planned or decided before it happens
*post hoc ergo propter hoc
an informal fallacy that states: "Since event Y followed event X, event Y must have been caused by event X."
*vaccination 疫苗
the process or an act of giving someone a vaccine (= a substance put into a person's body to prevent them getting a disease)
*diagnosed (原型動詞diagnose) 診斷
able to be discovered or identified
*autism 自閉症
*detectable 檢測
identify the nature of (an illness or other problem) by examination of the symptoms
*subtle 隱約的；暗淡的；不易察覺的
(especially of a change or distinction) so delicate or precise as to be difficult to analyse or describe