Difference between slave and submissive
There is no universal understanding of the difference between a slave and a submissive, so I'm going to defer to My friend Master Skip Chasey who has defined the differences, loosely paraphrased as follows:
A PHYSICAL act. One inserts and one is inserted into.
A Mental act. One directs and the other complies with that direction
A Spiritual Act. One (an Owner) finds obedience personally and individually and is then qualified to direct the other (slave) through training and discipline with the intention to cause and assure obedience.
Obedience can be understood as a connection. That connection can be with others, or to something less tangible, but it always makes us a part of what or Who is obeyed.
Most of us prefer to stay at the Dominant/submissive level because of its being a mental relationship. The ego can remain in control, be un-threatened, and remain our premiere self identification.
Where we see ourselves is a strong clue about where we are in our development and evolution, or how important any of this is to our lives in the first place.
Just as it would be a severe moral crime for Pat Robertson, the evangelist, to live My life, it would be just as serious a moral crime for Me to live his life. What is "right" for us ultimately must be received through our obedience, not rules.
Only those who are authentically Master/Owner or slave will ever find their evolution into the spiritual through BDSM. For those for whom it is not a created and authentic pursuit, BDSM will remain a part of their lives serving as entertainment, or more, that benefits their lives, but not the path of their life. Life is progressive. Where we are now is only a phase to where we will be next. Deciding to stay where we are now is death, as a law of nature describes that we are either growing or dying.
Contemplating where we are now is critical to knowing who we really are, what we should be learning now, and what might be coming next. Congratulations, therefore, on your question.