2000 BC Here, eat this root.
1000 BC That root is heathen. Here, say this prayer.
1805 AD That prayer is superstition. Here, drink this potion.
1940 AD That potion is snake oil. Here, swallow this pill.
1985 AD That pill is ineffective. Here, take this antibiotic.
2000 AD That antibiotic doesn’t work anymore. Here, eat this root…