All this is important because the answers to the questions here help in determining which of your fellow man are off their rockers, and have the delusion from God that is mentioned in 2nd Thes. 2:11
So it's a test? We're poly believers, I thought we had to be off our rockers to gain admittance to this place?!?
But in all seriousness...
How do you evaluate doctrine?
So if I want to understand a topic, or evaluate a teaching someone gives me, I'll go to the scriptures. That can be anything from looking at the verse in question in context, evaluating a handful of verses, or doing an exhaustive study of scripture on the topic and where are the words are used. How detailed I go depends on the scope and difficulty of the question. It's become easier with time as I have grown the mental bank to pull up many applicable verses.
My practice is to take the scriptures, as they are, in their plain English literal meaning, and compose an understanding from what they tell me in a logically consistent manner. In other words, take them as they are with a child like faith. I'll only view things metaphorically when the passage demands it.
I really dislike the just so stories preachers tell to explain away the plain meaning verses; they seem to obfuscate more than illuminate and at times are contradictory with each other or scripture. Same for using one verse to dismiss another while ignoring the full context of everything else in scripture. I also dislike the tendency of some to explain away literal means using a metaphorical explanation (e.g. viewing Song of Solomon as only an allegory of Christ and not as the literal love poem it is [also?]; or explaining away the Mark of the Beast as merely symbolic). So too for the attempt to explain away clear commands using unclear examples in the history recorded in scripture.
I usually only go to commentaries if I'm struggling with understanding something and need more ideas or am doing a deep dive on a subject. But I don't view them authoritatively (i.e. "see, this idea is right, mr. so and so says so").
If faced with a difficult question I will also pray to God for wisdom and knowledge. And if this revolves around a matter of difficult application in my life I may fast and dedicate large blocks of time to prayer on the matter. And I trust from principle that the Spirit is trying to lead me in my walk in Christ (imperfect though I may be in following).
How important is the context and usage of a word compared to say the definition of that word according to a concordance?
I'm not sure what to say here. My sense is they need to be consistent with each other. The definition should fit the grammar and the logic of the prose. But usage elsewhere can help one better understand the meaning of the word (translation isn't a 1 to 1 thing). Sometimes I'll see someone argue for an interpretation based on an alternative concordance definition not in accord with usual translation, but which if accepted would make logic of the prose to become contradictory. I don't care for that.
But neither am I shy to argue for alternative renderings of words, especially when one can see the known bias of translators come through in the way different translations render words. And I tend to hold concordance meaning above any individual translation choice when various Bible translations disagree; esp. when the odd man out is one known for occasional idiotic renderings.
But I don't really have the knowledge yet to get into making interpretation of individual verse translations based on textual differences between original manuscripts/families.
Most of my foundational understandings of doctrine came without diving into concordances and dictionaries; just systematic study of all scripture. But as I've dived deeper into specific topics I've gone to them more and more for fuller understandings. But I'm very suspicious of arguments that are based entirely on a single alternate rendering of the word while disagreeing with tradition. Especially if there are extant early commentaries to the contrary from native Greek speakers.
Looking up meanings in a dictionary is pretty straightforward though. But if a concept of mine relies on an interpretation of the grammar of the original language I hold it as highly speculative as I'm way way out of my depth there and will say so.
How much weight do you give the traditional interpretation of verses?
It's a gut check. My initial conclusion is draw just from the plain understanding of the scriptures. But if the conclusion I draw differs from tradition then I need to study deeper to ensure I interpreted it right. On the one hand, tradition is often wrong, so I don't start with tradition but scripture. But if my idea has never been held before by anyone, there is a good chance it's wrong. This isn't a strategy particular to scriptural interpretation for me, I do a similar same thing in other fields of endeavor.
But it is tricky, tradition can be a mixed bag. Different streams of Christianity conflict. Tradition changes. For example, Christianity universally condemns polygamy; that's the tradition. Yet if you look in history they didn't at the first, and didn't for as much as 1600 years after. We can see why it changed, and it wasn't because of scripture but pagan tradition while polygamy being ok is consistent with the OT and the early practice; which argues very strongly for it being ok. Especially since most of the condemnations rely on questionable interpretations of NT verses that don't directly address it and which the early church fathers didn't feel were condemning of it.
Another example is the headcovering. There are many just so stories and theological explanations for why it doesn't apply today. Modern tradition says no. Yet the plain English reading says yes. And the balance of tradition (the first 1900 years) say yes. The illuminating thing is the tradition only changed at the beginning of the coming of feminism (new, unscriptural, anti-God motives) and that is when the explain-away ideas arrived too. That's not to say tradition can't be wrong or late changes to it are necessarily wrong (e.g. the corrections of Reformation being 1400 years late doesn't mean they're wrong), but 1st wave feminists are hardly Martin Luther figures arguing against church traditions that are clearly contrary to scripture.
Take poly again, that we are coming to this idea during a time of sexual liberation might suggest this isn't coming from a Bible ideal, but us trying to join the party while feeling good about our faith too. But the pro-poly message of the OT, the consistency of the scriptures on the matter and the history of the change in theological understanding of the idea in the early church (the earliest pro-monogamy treatiste admits it's not from the NT but a 'new revelation') tell me that this isn't simply us trying to bolt cultural changes onto the scripture (even if maybe that's how some got here). I have argued polygamy as a good if you can't beat em join em strategic rejoiner to the culture war, but that's not the source from which my pro-poly ideas flow.
No I don't want to debate those here, I'm just giving examples on how I've handled the complexity of tradition in a logical way.
So tradition informs, but it doesn't dictate. If I lived in 105 a.d. I'd have a different answer; but over 2000 years tradition has shifted so much and in so many contradictory ways its impossible for any one tradition to be definitive in an of itself. People within a single stream of tradition will from bias argue for theirs. But from an unbiased outside perspective, choosing one or another tradition requires some form of judgement external to any one tradition.
I more look at the broad scope history of tradition than any one tradition. I usually only look at individual creeds or Synod statements if I'm wanting to understand the history of a particular stream of thought. The Apostles and Nicene Creeds being exceptions which carry a lot more weight than other creeds.
In the case of support for a doctrine or position coming from non-canonical books, do the verses carry as much weight as those in the regular biblical books?
Really haven't done much of this. But mostly because I'm not well versed in them and my bible study tools don't draw them in.
I'm not one to dismiss non-canonical books out of hand; especially those accepted by some churches as canonical; I'm pretty much open to any text that a part of Christianity accepted as from God. In theory, they get more weight than commentaries but maybe less than canonical; with those books no churches accept as canonical being towards the low end. But if I have to go to the non-canonical books I'm probably dealing with something where there is a lack of information in the canonical ones or I'm trying to fill in a hole of understanding or logic or trying to show what the common first century understanding was on something (a popular though fake scripture can't tell us the Truth, but it can tell us what people then commonly believed).
Yes I know all the above is a very logic heavy approach; more on the limitations of that another time.
here is a subject that might be fun.
