There you go again, using emotive terms like "boastful".
I know many of the people that have posted on this thread personally and a more modest, self effacing bunch I would struggle to find.
For the most part, as a nation, we Brits tend to understate our experiences rather than boast about them. It's just our nature.
In Scandinavia I would have to say they tend to be even more reserved. If someone there tells you it's "a bit cold" it's probably life threatening at least.
Looking through this thread, most people that have expressed a preference for natural materials also clearly acknowledge that synthetics function well in certain conditions and have their place.
I can only comment on my own experience, which few would describe as just "backyard" and while I would agree that synthetics will perform well enough to support life in extreme conditions, for comfort in SUB ZERO CONDITIONS (Note the title of this forum.) and extended expeditions, I would choose natural materials more often than not.
I suppose we are all free to judge each other's experience, or lack thereof, as we see fit. After all, the internet, even for Brits, is hardly lacking in unsupported claims. We each have to decide for ourselves whose claims we trust and whose claims be believe are just hot air.
I have stated in virtually every comment I have made in this thread that under certain conditions natural materials work just fine. Apparently for some reason, you chose to focus on every other statement regarding how some people do not travel through the woods, or make unverifiable claims about their experience with respect to the woods. The focus is curious considering I have not named a single name, or even hinted at who those people might be, or even implied that they are members on this forum.
That however completely dodges the actual discussion here. You can take offense to my use of emotive terms, or more exactly what you see as emotive terms (some things hit closer to home for some than for others), but that data does not make. Whether you like me as a person, or like the way I speak, or how I write, has very little effect on the insulating ability of any material we have been discussing here. Attacking me based on my attitude, or the terminology I use seems to be a poor substitute to actually debating the substance of the argument.
We are still to have anyone here present any scientific evidence which would support the claims being made. I know, I know, science does not matter, it is the work of the devil, etc. That being said, Big_Swede asserted that he is in possession of copious amounts of precisely such studies. I think it would be wonderful if he shared them with us, so we can all study them and learn. I think it would greatly reduce the number of these threads if one of us ever produced any tangible, verifiable evidence.
Oh, and just as a side note on the "title of this forum", it's -15C outside where I am right now. Please excuse my confusion regarding the question, but not all of the members here seem to share your interpretation. Some have chosen to disregard my comments because all my experiences were based on SUB ZERO environments, while others, like yourself, insist that those are the only ones that matter. If you would like, I would be happy to provide some "sub zero" pictures as well if it would help the discussion.