““A space that is empty in the sense that it doesn't contain masses is nothing but a special case of the above. Looking at it from the four-dimensional vantage point, space and time are interwoven according to the laws of special relativity theory. Space proper is Euclidean in its limit of vanishing gravity-trajectories of free fall are the straight lines already known from Newtonian physics. I will not go into detail considering space and time together in that case. Suffice it to say that this "empty space-time," too, can be described by a field; it is just one specific case among many others, and doesn't stand out.””
