When we describe or define things, whether they be objects or materials or, more generally, events of any kind, we can only do it in terms of our direct or indirect perception of their properties, in fact we could argue that things just are their properties. However, space is not something the properties of which we can directly perceive, that is we cannot see, hear, touch, taste or smell it, and it is very difficult to describe something that does not affect any of our senses.
Describing something with which we are familiar through our senses is easy; for example, telling you that I wrote these these notes on a pad resting on the table will be a sufficient description for you to know what I am talking about; you are familiar with writing and, although you probably have not seen the table to which I refer, tables are so familiar that, without going into a detailed description of its properties, just the word ‘table’ would conjure up a mental image sufficient for this purpose. However, if I was trying to sell the table via telephone, email or on the internet, the prospective purchaser would require a more detailed description of its properties, such as it will seat four people, it is made of light wood, which gives it a pleasant grainy appearance; it has four legs and so on . . .
Taking a less familiar example, let us say that I have just been asked about ‘yellowcake’ by a bright 10 year old child who has only a vague idea that it has something to do with nuclear energy. Unless I am able to show the child some yellowcake, or a picture of it, I will have to rely on a description of its properties: that it is yellow, in the form of a coarse powder which is insoluble in water and it is dense—uranium being the heaviest natural element, a handful of yellowcake feels quite heavy—and it causes a Geiger counter to tick rapidly. If I am able to show the child a picture of it they will be able to discern some of the properties themselves; the yellow colour and possibly the fact that it is a coarse powder, but they would be unable to detect the insolubility and the density or the fact that it is radioactive. However, a person working in the delivery end of a uranium processing plant, where they handle many drums of yellowcake every day, would not need the property descriptions at all, in fact they need not ever to have even thought about the properties themselves, they know what the properties of yellow cake are because they are familiar with both it and what is meant by the warning signs about radio-activity that are plastered all over the drums and their work area.
What I am trying to convey here is that there are only two ways we can know an object, material or event, the first through a description of its properties and the second through direct contact with it.
This is a very shallow explanation of property descriptions and perceptions, however there is a good introduction on appearance and reality in the first chapter of Bertrand Russell’s great little book The Problems of Philosophy, which also has chapters on the existence of matter and the nature of matter.
Ironically, although we live in space and are necessarily in direct contact with it, when we are asked to describe it, define it or explain what it is, we are lost because something more than a cataloguing of its properties is demanded. It’s as though I have described the table that I mentioned above in terms of the properties and even added dimensions, density, and so on, and you respond by saying, ‘Yes, that’s all very well, but what is it?’
When it comes to space, despite it being defined and described in terms of its electrical permittivity, magnetic permeability, curvature, transparency, rigidity and so on, people like me will still persist in responding with, ‘Yes, that’s all very well, but what is it?’ Frustrating as this question may be, in the case of space it is important because the asking of it implies that space is something more than the sum of its properties.
We could take the view that objects, materials and events just are their properties, apply this standard to space and say that space just is the sum of its properties. Let us try pursuing the example of yellow-cake in this context: taken together the properties we used to describe it earlier do not say what yellowcake is, however, in this case we are able to probe more deeply to see what it is that gives yellowcake its properties. The size and complexity of the uranium atom itself produces radioactivity; yellowcake is a chemical compound comprised of atoms of uranium and atoms of oxygen in the ratio of three uranium to eight oxygen, also known as triuranium octoxide, with the chemical formula U3O8. It is this particular combination of atoms and the way they are arranged, in a layered lattice, that give yellowcake its properties of colour, density, radioactivity and so on.
Ultimately it is the pattern of the layered lattice that makes yellowcake what it is. This is not to say that the pattern pre-exists without the yellowcake, on which each instantiation of yellowcake models itself; what I am saying is that the material that has this particular pattern of specific atoms and molecules just is yellowcake. Knowing its particular pattern means knowing what an object, material or event is, and we should be able to apply this principle of knowledge through patterns to resolving what space actually is. You can read more about what I think about patterns here.
Following this principle of knowledge through patterns, we ask why space has the properties that we perceive and measure. That is the real motivation for the questions, What is space? What is it that has curvature? Why does space have the values of permittivity and permeability that it does? What is it that waves when an electromagnetic wave passes by?
Earlier, we dismissed the relational theory of space on the basis that it does not appear to satisfy the requirement for a space with the degree of substantiality necessary to bear any of the properties attributed to space, so now we are obliged try to find out what gives naturally existing space the necessary degree of substantiality to support the properties that we are able to infer.
Inferring the properties of space
Space is transparent to light, that is it has the property of optical transparency. When I say ‘transparent’ I mean that we are able to see objects that are separated from us by space, which must mean that light is able to traverse space in some way. Of course, all the space with which most of us are familiar is filled with air and we might reason that the air has something to do with the transmission of light, that the air either allows the transmission of light or it assists it in some way. However, using a little ingenuity, we could construct a vacuum chamber with transparent walls, for example a bell jar, and withdraw the air from it so that only space remains. This would enable us to ascertain that light still passes through the vacuum as well as the transparent walls. In other words, all that remains in the chamber is space and, since light still passes through it, we must conclude that space is transparent to light. Even if we are unable to achieve a perfect vacuum in the chamber it is easy enough to ascertain that the light is no dimmer than it was when the chamber was full of air, as would be the case if it was the air that was facilitating the passage of light through the chamber. For the sceptics, more complex arrangements may be made, but the results will be the same; space either allows the transmission of light or it assists it in some way.
We are able to ascertain this without having any idea of what either space or light might be. However, at this stage it is not clear whether space just allows light to pass through it or whether space plays an active role in the journey of light.
It is possible that a source of light, the sun say, simply emits the energy in some form, for example packages of some sort, and space offers no resistance to their passage so that the original packages are able to travel from the source to the perceiver without hindrance. It is also possible that the source of light somehow disturbs space and it is this disturbance that travels through space in much the same way as we perceive the energy of a stone dropped into a pool of water spreading through the water in waves. However, we don’t know whether the energy is always in the form of packages or waves or sometimes one and sometimes the other or sometimes a mixture of both.
On the basis of the foregoing, we may say that because light is a form of energy, whether space does play an active role in the movement of light, or whether it simply allows light to traverse it, means that the medium of space is at least compatible with energy. Whether it means that space itself is a form of energy is the question to which we will now turn.
Is space energy?
Interestingly, there would be few problems gaining the acceptance of a description of space if we were able to say that space is matter of some kind with three dimensions and so on, and that was an end to it. Consequently, it seems odd that even though we live in space, so it must exist in some form, we are unable to simply accept this fact. When we say space exists, because it is not obvious to the senses, we are asked to explain further. Anyway, that is the case, so we will try to explain further.
We have already concluded the impossibility of something coming into existence from nothing and reasoned to the stage that it is most probable that only one fundamental entity exists, that is space, and that it has always existed; that it is the natural state of the universe for there to be space. Having decided that space is prior and fundamental, we want to know if space itself is energy or if space precedes energy or whether something that emerges from space precedes both energy and matter. In other words, whether there are intermediate steps between space and energy and matter.
When we consider space to be something, some ‘fundamental entity’, it is usually taken for granted that it is some material entity. If space is material it can exist only as either discrete elements or as a continuum so we will consider these alternatives.
If space is material and the material is discrete, it means that space is comprised of separate particles of material. However, because space is the only thing available to keep the particles separate, the idea that space is discrete leads us straightaway to the edge of a slide into a regress into asking again what that separating space is; is it a discrete material and so on . . . Moreover, having decided that space is all there is, because discreteness requires separate particles and because the particles have to be particles of some material, the conclusion that space itself is not material would be a contradiction.
If we postulate that space is material and discrete, the only alternative appears to be the relational theory of space, but we have rejected that, therefore, we must conclude that either space is not discrete or space is not material.
Space as a continuum
If the material of space is a continuum, the regress problem caused by discrete particles does not arise, however the continuum concept raises serious concerns. If space is material and a continuum it cannot be flexible because there are no parts. Having no parts means there is no way for there to be relative internal movement, with the result that a space continuum would be a rigid lump of material.
Of course the advocates of a space continuum may argue that the material of a space continuum is inherently flexible and, therefore, able to be flexed. However, for a material to flex there must be relative internal movement, which requires that one part of the material be able to move in relation to other parts, which would require that even a continuum must have parts. Furthermore, if the continuum of space does have parts we have to regard the parts as being discrete and that takes us back to the previous problem of the regress into determining what the space is that separates the parts. Consequently, even if for the sake of argument we allow that a continuum might have distinct parts, the argument that the material of space is inherently flexible is a difficult argument to sustain in the face of the requirement for relative internal movement between these parts.
Nevertheless, the advocates for the continuum of material space may still argue that even though there are parts, there is no space between the parts because the boundaries between the parts are contiguous, so continuity is preserved while the boundaries provide shear-lines to create the possibility of relative movement between the parts. However, even if we accept this argument, while the parts may move relative to each other along the shear lines, they have no free space into which to move. Another way out for the continuum advocate might be to suppose that, while there is no immediate space for the first part to move into, the moving part may push the next part along and that part the next and so on, ad infinitum, so the parts move as a train and not in relation to each other. At the same time there is nothing to stop the ‘trains’ moving in relation to each other along the shear boundaries while maintaining continuity through the contiguity of the boundaries. This is a disjunctive argument which assumes either that there will always be somewhere for the leading part of the train to move into, that is that space is infinite, or that the geometry of space allows the leading part of the train to move simultaneously into the space that would have been created by the last part of the train.
One problem for the first disjunct is that of moving an infinite number of parts. Even if the material space has no mass, the simultaneous movement of an infinitely long row of parts is not possible. This is because the parts of space, no matter how small, must be considered to be rigid, the last part in the row would be many light years away, perhaps an infinite number, yet it would have to move simultaneously with the first which, according to the special theory of relativity, is not possible.
With regard to the second disjunct, if space has a geometry that allows the leading part of the train to move simultaneously into the space that is created by the movement of the last part of the train, it might allow some flexibility in a region so small that relativistic considerations were not large enough to be of concern. However, this would require a space with a very tightly curved geometry, for which there is no evidence. For detailed and clear explanations about the geometries of space, see Graham Nerlich’s Shape of space, the received text on the subject.
Another problem with space being a continuum would be that, even given all of the above concessions, only one direction of relative movement at a time is possible, so flexibility in only one direction at a time would be possible. In consequence of this space could not be simultaneously flexed at ninety degrees to the first way, or any angle, because the boundaries are shear boundaries and ex hypothesi contiguous, and since it would not be possible to form complex curves, space could only be flexed in such a way that two dimensional waves might be formed. An attempt to avoid this objection may be made by claiming that the relative movement along the shear lines in one direction need not be completed before the movement at an angle is begun, making it possible to form complex curves. However, this tactic presupposes flexibility in that the only way for part of the whole not to be moving while another part is moving, is for there to be some flexibility between the parts.
Let us see what will happen if flex in two directions simultaneously is attempted. On the simplest analysis, this would result in one train of parts moving in direction A and another train of parts moving in direction B at an angle to A. However, if the train to A is moving, any simultaneous movement towards the B direction will require the train to B to cut across the still moving train towards the A direction, which would cause the equivalent of a train smash! It may be argued that if the train to A moved a small amount and stopped and then the train to B moved a small amount and stopped and then A . . . and so on, so that the flexing proceeded incrementally, the problem would be overcome. However, even if this could be made to work, there is still the problem of the infinitely long trains and relativity to overcome.
It may also be argued that vortexes of space could be formed because only movement along shear lines is required and shearing along contiguous boundaries would be feasible. However this move also fails because a vortex presupposes an increasing circumference so the outside arc of any part would be longer than the inside of the arc and, consequently, would require flexibility within the arc..
I have only considered the discrete and continuum hypotheses and the objections to them both in two dimensions, but if the objections cannot be overcome in two dimensions it does not seem worthwhile pressing the case to higher dimensions. We must conclude that a continuum of material space is not possible.
The energy alternative
The objections to the discrete and continuum concepts of space are all based on the assumption that it is a material space that is under consideration. However, it is not necessarily the case that space should be comprised of some material, in fact, considering the objections just raised and there insolubility, an alternative hypothesis is required. Of course there may well be any number of hypotheses about the nature of space including: a mathematical construct rather than mathematical description; a geometrical construct rather than a geometrical description; a graphical construct rather than a graphical description; strings; a completely inert void, information or noise. All of these hypotheses have been and are still proposed but accepting any one or a combination of them would mean that this inquiry must end here. Therefore, the alternative that we will consider from this point on is that space is an energy field.
I acknowledge that we have reached this stage by a process of eliminating the material alternatives rather than by a process of deducing or modelling the energy alternative, however, on the basis that there do not seem to be any other viable alternatives, we will continue with the next part of determining the nature of space as an energy field; the creation of event cells.
- Our inability to sense space in any way makes it almost impossible to describe.
- The are only two ways we can know an object, material or event, the first is through a description of its properties and the second through direct contact with it.
- Asking what space is implies that it is something more than the sum of its properties.
- Only absolute space gives the necessary degree of substantiality to support the properties that we are able to infer.
- Whether space does play an active role in the movement of light, or whether it simply allows light to traverse it, means that the medium of space is at least compatible with energy.
- Does space precede both energy and matter?
- If space is ponderable material it can exist only as either discrete elements or as a continuum.
- Postulating that space is material and discrete, requires the relationist view of space, which we have rejected.
- We also conclude that a continuum of material space is not possible.
- The alternative that we will consider from this point on is that space is an energy field.