Is space an entity?

yes i think its the one that everyone mistakes for god

No, its a lack of physical matter.

(Now people will say "But there is microscopic matter in space" and to them I say this *pokes tongue)

I, Edward N. Haas, am the 73 year old author of a now 52 year old cosmological system called: "Esoptrics, The Logic Of The Mirror". Esoptrics says space is indeed an entity. How so?! Esoptrics says the universe is composed of 3 kinds of ultimate entities: (1) the 2^256 kinds of piggyback forms, (2) carrying generators, and (3) the lines of tension generated by the generators. Esoptrics says each of these 3 kinds is only LOGICALLY rather than PHYSICALLY extended. The lines of tension are the various kinds of sense images we feel. The carrying generators are what give material objects whatever level of impenetrability they have. The piggyback forms, because they have no level of impenetrability, are space. They are a kind of space composed of ultimate units each of which is only logically outside of all the others IN THE ORDER OF SEQUENCE. Also, the forms are a kind of entity whose internal characteristics can to no extent be detected either by our unaided senses or any man made instrument. Thus, whenever we try to experience them, all we can feel or detect is a blank which, nevertheless, has, TO OUR SENSES, length, width, and depth. Esoptrics is the first system in history to explain how space and its occupants can have ultimate parts (TO OUR SENSES, these ultimate parts are 10^-47 cm. in size.) which are only logically outside of one another in the order of sequence rather than physically outside of one another in space. It is thus the first system in history to give an explanation of how the entire universe can be a single point which, nevertheless, is LOGICALLY divided into an astronomical number of points each of which is LOGICALLY outside of all the others and in a LOGICALLY determined order. Those interested in full details can contact me at htoknow@yahoo.com.

All of space taken together, yes. A small amount of empty space, no.

Is nothing an entity?

In a pure Newtonian view, space is nothing but an abstraction of the human mind and only has any importance in the presence of a frame of reference. This theory has certain holes though. The famous example is the bucket problem. Say you were to take a bucket full of water and tie a rope to its handle. You then tie that rope to something so that you have a bucket full of water hanging from a rope. If you were to wind that rope up and release the bucket so that it started spinning, you would observe the water in the bucket tend to the outside of the bucket. This is often shunned off as simple inertia. the water in the bucket is spinning and the water tends to stay in motion towards the outside of the bucket. That is assuming the bucket is spinning from the reference point of the observer standing next to the bucket. The problem comes from the reference point of the water. To the water, the world around it is rotating. Who's to say that the water is really rotating at all? this leads to the idea of an absolute frame of reference, or space as a physical entity.