I think they are similar. However, there is a difference. Let me use an expression as an example. I might say something like this: "I want to live. I don't want to merely exist."
By 'I want to live', I mean that I want my life to have meaning. I want to do something with my life.
By 'I don't want to merely exist', I mean that I don't want to just sit and do nothing. I don't want to just breathe and have a beating heart. I want to do more actions to make my life have meaning.
Ok. I hope that example was helpful