What in the World(view)?
A worldview is the collection of ethics, ideologies, philosophies, and cultural perspectives with which a people, community, group, or individual apprehend the world, whereas the world is the physical, emotional, and intellectual environment in which said peoples, communities, groups, or individuals live.
This distinction seems very self-evident but people often seem to blur the lines between the two in discourse. When discussing the Heathen worldview, vague, often sweeping, statements will be made. This is done without considering that 11th century Norway was a very different place to 5th century Britain which, in turn, was a very different place to 1200BCE Sweden. Because of this, the ever-changing world in which the pre-Christian Germanic tribes lived is effectively masked by the modern desire to have a single, easily apprehendable worldview that can draw from as many potential sources as possible. Instead of reality, we find a hypothetical "ideal world" created without the variation present in historical reality.
This ideal world becomes the setting, and part of, the Heathen worldview and people stop looking at what the people thought about the world. Instead, they look at their interactions with the world. When modern commentators look at a sword, they often see a romanticised weapon, hearkening back to a time of honour, and they may shun any further weaponry advances as "unHeathen". After all, the Vikings (sadly, it is far too often that the entirety of Germanic culture up to the year 1066CE is summed up in the word "Viking") never used firearms. This mindset misses the point. Historically, we can find that the Germanic peoples were relatively technologically advanced, at least when compared to neighbouring cultures. They had smiths so talented that, even today, historians struggle to explain (let alone reproduce) their skill. If we apply their worldview to our world, rather than to theirs, we can see that an embracement of technology is absolutely able to be considered a Heathen ideal.
This attitude of looking at the world, rather than the worldview, also leads people to look for ways to justify their previously held ideologies within the framework of Heathen worldview. Rather than adapting to a Heathen worldview, attempts are made to adapt that worldview to more modern agendas. As such, an entirely new worldview is created; often so different from the worldviews that would likely have been held by the ancient Germanic tribes that it cannot be recognised as "Heathen" whilst retaining any semblance of intellectual honesty.
All of us fall prey to this, at times, but it is a willingness to acknowledge our errors that will allow us to grow and truly adopt a worldview that our historic forebears would, perhaps, have identified with or, at the very least, recognised.
How can I suggest that there is no single "Heathen worldview" yet, at the very same time, promote the adoption of a "Heathen worldview"? It is because that, whilst there would be both regional and temporal variations between the various tribal and family groups, there would also be certain recognisable commonalities. I believe it is extremely important to lay down these commonalities as a kind of "core" to the worldviews that can all be described as Heathen.
The first, and most obvious, commonality is community. This is not exclusive to Heathendom, of course. Prior to the Industrial Revolution and the ensuing rush to the towns, the community was of great importance to most people. There were very few social "safety nets" provided by the state for the less than fortunate and, so, people had to rely on the good will of their community, in hard times. In the Germanic context, one of the most severe punishments that could be meted out to an individual was outlawing - an exiling from the community and a withdrawal of that community's protections. Conversely, to be a part of the community was to be protected against the perils of the outer world - those places beyond the limits of the community's territory - and to share in the boons of that community. These benefits could literally be the difference between life and death.
Next is belief in the supernatural. Often overlooked, the belief in supernatural entities was very much a common ideology across the Germanic world (and beyond), to the point that the average pre-Christian Germanic person likely took the existence of wights for granted. They were very much part of everyday life, and offerings would regularly be placed for them. Beyond these beings, a further (supernatural) belief was in magic. We have countless archaeological finds of artefacts with amuletic symbols engraved on them, and we have examples of charms from post-conversion eras that very much show a continuity of earlier belief. There were even individuals considered to be magical specialists - those who had special training or knowledge of matters magical. These magic users were held in awe by the common person and, often, feared.
Hinging off the supernatural, another core Heathen ideal is world acceptance. What this means is that the Heathen does not live their life in anticipation of an afterlife reward, such as may be promoted in world rejecting religions such as Christianity. Instead, a Heathen lives their life according to the belief that their actions have an immediate impact in the living world. Where right action would bring right reward so, too, could wrong action bring fitting punishment of a more immediate nature than is suggested by world rejecting ideologies.
Widespread throughout the pre-Christian Germanic tribes was the concept of ancestor worship. Without our ancestors we, quite simply, would not exist. Furthermore, their actions ultimately led to the particular situation into which each of us are born. For this, at least, they deserve gratitude. There is ample evidence that the pre-Christian Germanic peoples would regularly give offerings to their ancestors, and we can even find examples where burial mounds have been reopened to deposit or retrieve items. It seems likely that families would hold particularly notable or cherished ancestors in especial esteem.
At the heart of ritualised offerings was the wider concept of reciprocity. Reciprocity is the practice of an exchange between parties for mutual benefit. Sacrifices were not made to the gods so much as pure acts of devotion as much as they were made as part of a transaction - payment for a good harvest, or a victory over an adversary. The concept of reciprocity was not just limited to the gods, wihta, or ancestors, however. It also extended to human interaction. Gift giving was a major form of creating and maintaining solidarity - a person of wealth would be able to gain a favourable reputation by being generous to his family and friends. In return, they could expect loyalty and services.
Reputation was of significant importance to the early Germanic peoples. A warlord with a grim enough reputation could win a battle without even stepping onto the battlefield. A generous king could hold the loyalty of his people. There are numerous tales of how individuals sought prestige and good reputation through their actions, to the point that their names and deeds are recounted to this day. In a culture that places far more importance on a person's deeds in this life than on their guarantee of post-mortem "salvation", being remembered favourably was very much a high priority and this was a strong motivator to people's personal honour.
Beyond these, there will be numerous other concepts, with each one being embraced by some Heathen denominations and rejected by others. This does not make any of those denominations more or less valid than any other; it simply means that they are different. These differences reflect the inherently tribal aspect of Heathendom and should not be seen as obstacles to interaction. The Heathens of centuries past were great travellers and had contact with many different cultures. They certainly were not insular, and did not shy from others simply because they could be seen as different in some way. So, too, should the contemporary Heathen be able to live their own form of Heathendom without worry that another is "Heathening wrong".
In conclusion, the core ideals common to Heathendom of any form are: community; belief in the supernatural; world acceptance; ancestor worship; reciprocity; reputation. Different forms of Heathendom will almost certainly have varying ways of approaching these concepts, as well as placing differing levels of importance onto each one, but they will approach them. Focus on your own practice, and on these core ideals, and the rest will come.