This discussion will mostly concern early Gaelic matters. However, the concepts are related to concepts from other societies in northern and western Europe, especially the Saxons and Norse, and even to other Indo-European societies such as the Greeks or Hindi. That said, there are differences between those societies and the Irish, but I would direct the reader to other sources and the reader's own research in order to more completely understand those other societies.
In the cosmological meditation I posted a while back, one of the images that was central was the flow of a fiery water which was representative of brí , the flow of energy of all kinds, whether in the physics sense or other senses (such as emotional energy, the creative impulse, wealth, or the like). This is a very important concept which can be seen as underlying many aspects of early Irish society. Importantly for ethical considerations, it underlies the assumptions behind the Breitheamh (“Brehon”) law. This was a legal system, similar to the English Common Law in some ways, but very different in others, that governed the daily activities of the Irish until well into the Christian era. It was finally overthrown by the English when they invaded and conquered Ireland, to be replaced by the English system of law.
Basically, the system of law set procedures and guidelines for describing the social responsibilities and ties, personal economic power, and theoretical community reputation of particular individuals and their relations. By describing social responsibilities, it therefore described a system of ethics and moral behavior.
The basic picture of society as prescribed (and described) by the Breitheamh law was one of hierarchical relationships based on social ties and property. The theory seems to have been that those who had more possessions and more people obligated to them had more interest in the success of the community, which is a reasonable assumption in an agrarian/transhumant, decentralized society since it was the community which guaranteed the security of wealth. Degrees of authority were, therefore, granted on the basis of what was owed to one, and so largely on what one could afford to, and did, lend.
We should not, on this basis, think of early Irish society as being similar to modern capitalist society, however, as the theory also included assumptions of responsibilities that those in authority had to the community, not just privileges granted to them on the basis of their social position. They were given a higher burden of community support than those below them in status, but then they also were granted social privileges unavailable to those who were of inferior state.
There are other complexities involved in the early Irish social structure, but this will serve for a basic overview. For more detail, I recommend Fergus Kelly's A Guide to Early Irish Law and Early Irish Farming , along with the two-part article by Neil McLeod, “Interpreting Early Irish Law: Status and Currency”, part one found in Zeitschrift für Celtische Philologie vol. 41 (1986), pp. 46-65, and part two in ZCP vol. 42 (1987), pp. 41-115. These will not, largely, cover various exceptions, such as the status of religious functionaries like Draoithe or Christian monks, among others, but they give a nicely detailed look at the general structure of society (and, in the case of Kelly's Guide… , of the legal system).
After the social structure, the next aspect of Breitheamh law we will consider is the matter of Justice, and how society functions to maintain orderly life. There are few instances of punishment prescribed by the legal system, though there is much discussion of various criminal actions that can disrupt the calm functioning of the society. Murder, assault, and theft are all condemned by the system, just as they are in nearly every other society's social code of conduct. Punishment, though, is avoided in most cases in favor of various methods of redressing the social imbalance that occurs. For instance, if theft occurs, the object stolen, or its value, is returned to the victim. In addition, if the victim is of such a status that a theft would also indicate damage to his good name (“he is unable to take care of his own things, how can we trust him to take care of ours”), then that would also need to be redressed. This is done by means of the famous “honor price”, which is a value set on a person's good name and reputation. This value is largely determined by complex formulas laid out in the legal texts relating to how one fits into society's expectations and needs. This is defined by examining the property and clients of the person, or his or her relationship to someone who has property. “Property”, in the early Irish conception, would be what we would call Capital Goods and Real Property. That is, it was considered to be, for these purposes, land and those goods which have economic value related to the trade of the person in question. “Clients” are even more important in the early Irish system, though, as it is through patronage that one gains a following to back one up in petitions to the community as a whole.
This brings us to the metaphysical assumptions behind the Breitheamh law system. One of the most important is that wealth, fertility, authority, sovereignty, and so on comprise a real force flowing from the Otherworld. The Irish term that I use for this concept (and which I believe is the original use of the word) is brí , which is a word that means, roughly “strength, vigor, significance, meaning”. It is the root of briocht , which means “charm, spell, amulet”, and of the name of the goddess Bríd , or Brighid. It is, therefore, the undifferentiated matter, without form or substance, that underlays all existence that we perceive. It is the very material of the Otherworld itself. It is by transference of this material between the world we can perceive and the invisible Otherworld that the cosmos moves and functions. It manifests as intuition and creativity, iomas, energy, and as physical matter, depending on exactly how it is configured. The differences there are a discussion for another time, however.
Brí flows into this world along well-defined channels. We perceive these channels as bandéithe , “goddesses”, who are considered to be andéithe , “un-gods” or “chthonic gods”, and associate them with wells, rivers, and the land itself. On its own, this flow of brí is chaotic and wild, resulting in the wilderness and the meandering flow of rivers, among other things. However, some déithe (including both gods and goddesses) have learned, and subsequently taught us, their descendants, to form that flow into shapes and processes more conducive to cultural existence.
One of the most significant ways in which brí is made to serve society is through the institution of the Rí (“king”) or Ríon (“queen”). This is a person chosen for his wide range of clients and wealth, and given, as a result, a position of some importance. He acts as a tribal chieftain, but also in the function of a particular sort of priest. He is required to marry the local bandia (“goddess”), and from this marriage the flow of brí passes through him to the community as a whole, passing to his clients, and to their clients, and to their neighbors. The measure of success of a Rí or Ríon is in the quality of life in the tuath (“territory”) under his control, including such aspects as weather, the harvest, trade, wealth, and so on. The mediation of brí from the Otherworld into this world is the measure of the societal value of a Rí, and the failure of that, made explicit by the failure of the kingship in various specific ways (including weather, the harvest, and so on), should result in the replacement of the Rí.
At various levels, this dynamic is indicative of the general Gaelic conception of the order of life. A poet mediates brí as iomas, the inspiration and intuition that underlies poetry. A warrior has a set of different ways of acting as a channel for martial energies (fearg “anger”, for instance, but also more esoteric concepts such as lon láith “blackbird ardor” or riastartha “contortions”). All of these are variations of the basic model of energy passing from the Otherworld, into a specially prepared person in this world, and so transforming into practical benefits for the community. (There is an additional step, involving returning this energy to the Otherworld, but we will leave that for the moment, noting only that it is the process of sacrificial giving that returns this energy, in a continuing cycle.)