I thought it might be useful to define what I mean when I use words like ‘probable’ or ‘possible’, so I’ve created my own scale to define how likely I think something is to be significant. It’s meant for whether or not an astronomical correlation is meaningful to archaeological material, but it probably has general applications.
Example: The Sun rises over Stonehenge every day.
Something is certain if, by negating it, you effectively rule out any hope of having a meaningful discussion. It is possible that in the future data might prove things thought to be certain are not, but here and now certainty is the foundation from where we start.
Example: Stonehenge has intentional astronomical alignments in its architecture.
For something to be probable it has to have evidence in its favour AND be the only or far and away the most convincing explanation for a phenomenon. While a probable phenomenon is not certain, rejecting it would require an awful lot of extra explanation for events
Example: Stonehenge was built so that the entrance would face the rising Sun at the midsummer solstice.
For something to be plausible the concept has to have some evidence in its favour. There will more than one plausible answer to a problem. In this example the entrance does face the sunrise. However the site could have been built so that people approaching from the avenue were facing the setting sun at the midwinter solstice. I would argue the second is more likely, but the summer option is not contradicted by the evidence, so the winter explanation I prefer can only be said to be a plausible answer. Then there’s the other idea that both factors were deliberately planned…
Example: Only the elites saw astronomical events from inside Stonehenge.
A possible explanation is one that is based on reasoning, but has no real evidence for it one way or another. A well-reasoned possible explanation may be more convincing than a poorly-reasoned plausible explanation.
Example: Astronomy played no part in the building of Stonehenge
A problematic explanation will have evidence against it which will require a lot of explanation to fix. There will be other more convincing explanations of the same phenomenon. I’d argue the example is problematic because so many Stone Age and Bronze Age structures do share similar orientations.
Example: The aliens that built Stonehenge came from Venus
An unlikely argument is one that, if accepted, creates no grounds for excluding any other arguments at all.
The terms have no numeric values because that would be a bit silly. They are also deliberately bland. If someone prominent says something stupid. I would like to say that “Prof X’s work is problematic in places, and ultimately an unlikely theory”, rather than “Prof X’s work could be unpicked by a thirteen year-old in five minutes.”
In terms of combining theories, the hybrid will at most as likely as the weakest component that makes up the hybrid. The combination may also be less likely, but combining two possible theories will never make a theory plausible. That’s for my use to remind me how likely some of my own work is.
I’m open to criticisms of the definitions, the terms and even the name of the scale. I wanted to call it a Scale of Plausibility, but I cannot really if one of the terms defined is plausible.