Western militaries are struggling to comprehend how to effectively manage the rapidly changing character of contemporary warfare because the multi-domain model used to explain it is fundamentally flawed. How and why this is the case will be explored below. Finally, an alternative model will be proposed that is both simpler and provides a more holistic understanding of contemporary warfare.
Challenging The Model
The current multi-domain construct with its five extant domains (land, sea, air, space and cyberspace) dominates discussions of contemporary and future conflict in Western militaries.  This is particularly notable in discussions relating to some of the more intractable contemporary dilemmas such as “hybrid warfare,” establishing or countering large A2/AD zones; countering hypersonic missiles (especially when deployed in support of an adversary’s A2/AD zone), proliferation of low cost weaponised drones, the rise of the so called “like” war and the rise of autonomous and intelligent systems.
The current five domain construct underpins major intellectual lines of effort such as the US Army’s Multi-Domain Operations  and the Australian Army’s Accelerated Warfare  line of effort. If the underlying model describing the domains in which contemporary warfare occurs is flawed, any doctrinal framework built upon that model will also be flawed. The result would likely be continued frustration in trying to understand and effectively respond to the changing character of contemporary warfare. This isn’t to say that there aren’t smart people working on it, more that if the underlying problem isn’t clearly defined you may end up solving the wrong problem.
The Flaw In The Model
The primary issue with the current construct is that it emphasises the wrong thing at the expense of other more important considerations.
The defining feature of the current domains is terrain. All five are terrain descriptors albeit cyber describes an artificial terrain. This approach is flawed because it is ambiguous and arbitrary. For example the land domain could be further divided into sub domains such as; urban, jungle, desert and snow noting the vastly differing conditions, tactics and often equipment required to operate effectively in each.
The boundaries between domains are also vague when applied to real world scenarios (owing to a lack of consistent domain definitions). For example, Army has both rotary wing and fixed wing UAS platforms. While these are undeniably air platforms, their employment is in direct support of the land force aimed at generating effects for the land force. The same argument can be applied to Army’s water craft or Navy’s rotary wing assets (changing land to sea).
Consider a long range land based maritime strike system, a mobile surface to surface munition designed to project an effect with speed at range and into a different terrain type. Now consider a sea based land attack system. This is still a mobile surface to surface munition designed to project an effect with speed at range and into a different terrain type. Yet the two systems are treated quite differently conceptually.
In a 2017 speech to the Australian Strategic Policy Institute on the topic of building the integrated joint force, (then) Vice Chief of the Australian Defence Force, Vice Admiral Ray Griggs, described the multi-domain model as an approach that “leads to a focus on the ‘seams’ rather than the system as a whole.” 
In the multi-domain model this creates the problem of focusing attention on the terrainon/in which things occur rather than the effect that they have (both tangible and in-tangible effects). This creates mental barriers to achieving a force structure that is truly “joint by design.”
This creates the problem of focusing attention on the terrain on/in which things occur rather than the effect that they have (both tangible and intangible effects). This creates mental barriers to achieving “joint by design.”
Now consider what the current multi-domain view omits. It omits any consideration of the human element. This includes a wide range of issues that could be summarised as “hearts and minds,” and extends to cover own and end enemy forces, own and enemy civil populations and their respective political leaders. It is in human “hearts and minds,” that concepts like morale, morality, political narrative and the contest of wills reside. Any mental model aimed at understanding the domains in which conflict is fought has to take account of the human “hearts and minds,” element. The current multi-domain view is silent on this issue.
Despite being an artificial domain, cyber doesn’t address human social issues. As of 2017, the US DoD defined cyberspace as “a global domain within the information environment consisting of the interdependent network of information technology infrastructures and resident data, including the internet, telecommunications, networks, computer systems, and embedded processors and controllers.” 
The immediate problem presented by the current terrain centric multi-domain model is that many of the contemporary and emerging problems that need addressing are “cross domain,” in nature (and many are by design). Consequently it is difficult to co-ordinate a coherent response across domain boundaries when there isn’t a clear consensus of where the domain boundaries are. This in turn makes it difficult to work out where the responsibility for countering any given threat should lie. The lack of clarity adds an extra layer of friction to what is already a difficult problem set.
Change The Model
Since the existing domains are all terrain centric (four real and one artificial), the model can be simplified by consolidating the existing five domains down to two. By doing this, a binary domain construct emerges where the two domains are the physical and the information domains.
In the binary domain construct, the physical domain is simply four dimensional space time (three dimensional space plus time) and the information domain is comprised of data plus the intangible human elements described earlier.
The physical domain is defined as four dimensional space time in order to account for the effects of relativity (both special and general) on space based systems. This sounds more complicated than it is and for all terrestrial objects it is simply physical space and time as understood in the common meaning of them. Importantly, the electromagnetic spectrum resides fully within the physical domain.
The information domain is made up of the intangible human elements (morale, morality, political narrative, will to fight, etc) along with the data that describes the physical world. In this sense data is the codification of a physical object, event or process. Everything that exists and occurs in the physical domain can be codified as data and represented in the information domain.
Additionally, the information domain is not simply the current cyber domain renamed. It is more than cyber as it also incorporates the “hearts and minds,” of human society (the political, moral and ideological).
An emergent property of the binary domain construct is domain entanglement. The physical and information domains are tightly coupled in the sense that a physical object, event or process can be codified and represented in the information domain where it can be shared, analysed and studied. The knowledge gained can then be put to use informing subsequent decisions cycles from the individual to the strategic.
Not only does the physical domain overlap the information domain but the information domain also spills over into the physical domain. This is because all of the information stored in the information domain exists somewhere in the physical domain (minds, books, servers, hard drives, etc).
As previously mentioned the information domain is where the intangible human elements reside. This is what information operations, deception, coercion and concepts such as “like war” target. By manipulating the target audience through the transmission of carefully tailored messaging, the aim is to alter the target’s behaviour. As with data, the transmission process is physical (i.e conversation, reading, radio transmissions, fibre optic cables, etc) however the clash of ideologies occurs solely in the information domain, in the hearts and minds of the people involved. The results of these ideological contests, however manifest themselves physically through human behaviour (tactical or otherwise).
Ultimately though, since people live in the physical domain, war’s violence will manifest itself in the physical domain, with enabling and supporting actions in the information domain (i.e propaganda, coercion, deception, etc).
By adopting a simpler mental model a clearer picture of contemporary conflict emerges. One that puts physical and moral effects into focus rather than terrain. It’s time for an effects based model rather than a terrain based one.
About the Author: Chris Bulow is an Australian Army engineering officer with experience in training, brigade maintenance and higher headquarters roles. He is currently posted to the Defence Academy of the United Kingdom where he is undertaking a Masters of Science in Explosive Ordnance Engineering. You can find him on twitter at @C_Bulow.
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