It has three very different basic English equivalents: intellectual, mental, spiritual. It's up to the reader to decide, based on context, which of these is the best fit. Often I can't make up my mind. It's annoying, but it also reminds me why I like the German language. The implication is that the intellectual and the spiritual are closely related...
If you haven't looked around at the Legacy Project yet, take a few minutes to do so:
Our site is a gathering place for people interested in the enduring legacies of the many violent traumas of the 20th century. We are dedicated to exploring issues of remembrance in different cultures, in order to better understand the contemporary significance of historical tragedy.
[hat tip to Nurri]