P eople are a sort of robot, and people have consciousness. A conscious machine' does not contradict known laws of nature. Robots are purely material and consciousness requires something immaterial. This is dualism, and dualism can't explain how the material and immaterial could interact.
Robots are inorganic, and consciousness can only exist in an organic brain.
Perhaps an organic brain is required, for speed and compactness, but a robot need not be inorganic. Two things could, in principle, be identical at this moment, yet have had very different histories. A molecule by molecule copy of you wouldn't legally be you, but it would be a person. However, as a practical matter, something like infancy' may be necessary to train a robot to have consciousness. Robots will always just be much too simple to be conscious.