Use of en

Question

Is there away of knowing when to use en/ Dan's when refering to some of the above examples? Why would it not be right to say "Je crois dans la vie après la mort??

Accepted Answer

Hi Conor, 
Just to add to Chris’ excellent answer, the expression is -
‘croire en quelque chose’ = to believe in something
For instance -
Je crois en Dieu = I believe in God 
Il croit en nous = He believes in us
Hope this helps!

Answer

En is a general "in", it can also be used figuratively. Dans is the more literal spatial preposition "in".

In the sentence "to believe in life after death", the preposition "in" is not a literal "inside" and therefore en is the appropriate preposition to use.

Here is another example which demonstrates the difference nicely:

Être en prison. -- to be imprisoned.
Être dans la prison. -- to be inside the prison building (not necessarily as an inmate).