What is causal consistency in mongodb?

Thanks, @MaBeuLux88_xxx and @Stennie_X.

As I understand it then, basically causal consistency reinforces the idea that mongodb offers strong consistency across the cluster as a client will be able to read its own write. That’s it?

Another question is: Can the customer only do this if he uses read concern combined with write concern majority?

On the documentation page it shows this.
If this combination of read concern majority and write concern majority doesn’t happen, then does it mean that mongodb doesn’t guarantee strong consistency?

Thanks for the clarifications,
Caio