Right you are. There is no consensus about what exactly and fundamentally constitutes a consciousness. In my mind, there are a few things that characterise what I consider to be a consciousness.
1 - The perception of a subjective frame of reference through sensory experience.
2 - An independent internal thought process, with the capability to learn, reason, exhibit novel creative behaviour and be self aware.
3 - A non-deterministic thought process, that is, the consciousness is random on some level, allowing it to think differently when it encounters the same information under the same circumstances multiple times.

Additionally, building laws to limit the behaviour of robots is different from slavery, as the person who builds the robot is responsible for its existence. Under slavery, a previously free person is taken by force and compelled to follow an authority. Just as parents instill patterns of behavior in their children to improve their social cohesion, so too would robotic manufacturers instill laws of behaviour in their robots. This is not slavery, it is instilling instinctual behaviors into robots to allow them to co-exist with humans, instead of violently competing with us. It compels robots to be moral, and it would be incredibly immoral to produce a robot that is not prevented from killing humans. Androids would be protected by the same rights as humans are, and would not have to follow any authorities orders, as they are sentient, but would need to follow the same natural laws that humans are compelled to follow by governments, except by programming design, rather than the threat of force.