system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What does it mean that correlation does not imply causation?

I've read an example of it that left me just as confused as before. It went like this:

*If you say "Everyone who drank water in 1800 is now dead, so drinking water kills you", that's correlation without causation, because their deaths was not caused by drinking water.*

Only, their deaths weren't correlated with drinking water either, simply because humans don't last 200+ years. So, what am I missing?
gpt
>Only, their deaths weren't correlated with drinking water either

They are. They are correlated because both statements about these people are true: they drank water and they did die. That's the point. The correlation doesn't mean they died *because* they drank water. As you say, they died because people don't live 200+ years. The correlation does not imply causation. 

Many thing correlate while having zero impact on each other; they merely coincide.

Actual correlations:

Ice cream sales and murder.

M. Night Shyamalan box office and newspaper sales.

Use of Internet Explorer and the murder rate.

Mexican lemon imports and highway deaths.

None of these things is a direct causal relationship; they merely correlate.