Practical ideology

The concept of ideology is that of ideas.  The ideas that one has, that form the structure for how they think, what they think and what they believe to be true, makes up ones ideology. 
A practical ideology world therefore be one that is: sensible, practical, useful and pragmatic.  Hopefully you see the problem with such an approach.  A practical ideology is one that is founded upon shifting or changing foundations.  The pragmatic approach leaves one with the option to change as ones situation changes, or as ones perceptions or feelings change.  Personally, this would leave me very uncomfortable.  The idea of a personally defined and malleable ideology leaves one with no certain boundaries or structure for an ethic.
I would think that this would eventually destroy ones soul.