I haven't used Ruby on Rails as much as HTML or CSS. But even I've asked myself this question plenty of times.

"Descartes relies on God being an all-good being to believe it would not deceive him. So doesn't the existing problem of evil mean any God could still be deceiving our senses?"

There's another question more relevant to Rails I've also asked myself.

"How can I load one attribute from a record, but not all of them?"

Let's say I had a giant list of philosophy quotes. I want to get five random names from the quotes' authors. So I have a Quote model that has, among other things, an author column with their name. How do I get these names?

There have been many times I got that data this way.

Quote.order('RANDOM()').limit(5).map(&:name)

This works, but I have to load each attribute of each record. This isn't a lot for small records like philosophy quotes. But larger records means larger queries that burden the servers.

That's where the pluck comes in! It doesn't load the whole record, only the given attribute. It's a smaller query and the syntax is more explicit.

Quote.order('RANDOM()').limit(5).pluck(:name)

Now I have an easier way to get the names of old dead white men who can tell me why evil exists in the world. Presumably the answer isn't a lot of the old white men that haven't died yet.