Lets say science detemines in the future that consciousness is just thoughts about thoughts ( Higher oder Theory ) then you could look after that pattern or functionality in artifical neural networks and this way determine if that machine is conscious or not. In a way there a possible consciousness patterns that need to be determined if the are valid or a few of them together ( the ones I prefer ( Infografic ) in combination are a logical answer to me ) . After that you only need to look after these patterns in machine intelligences or other live forms. It´s only pattern matching and validation after that. I don´t accept magic or metaphysic as an answer for consciousness because metaphysic will become just physic when the definitive answer is found what consciousness is.