Thank you for that. I tentatively accept your assertion that the British study (summarized by the Youtube video I referenced) is not credible.
For science, I wrapped my body in a polyester blanket and wore a sun hat with UPF of 50+ and sunglasses so that none of my skin was getting UV at any significant intensity and spent half an hour in the mid-day sun. All sunglasses on the market from name brands reliably block UV. Polyester is very effective at blocking UV and like almost all fabrics will let at least half of the photons at most infrared wavelengths through. I did this prol at least 20 times. This protocol might have had some positive effect, but if so, the effect went unnoticed by the methods I used (namely, mere introspection and curiosity) or the effect was not large enough for me to be sure that the effect is actually there. In contrast, 20 minutes of mid-day sunlight on a cloudless day on my bare skin and into my “bare” eyes has a pronounced positive effect which are obvious to me.
(Also I once had a session in a machine that costs many 1000s of dollars that I climbed into naked that bathed me in all directions with red light and near-infrared light produced by thousands of LEDs. I did not notice the effects that I value the most from sunlight exposure.)
That strongly suggests that some combination of visible light and UV light is the cause of the effects I value the most. Here let us observe that the common LED light bulb produces no UV light.
I’ve never made the experiment as far as I can recall of exposing myself to LED light bulb light that is as intense in the visible spectrum as the mid-day sun is. (Frankly I would probably strongly dislike the experience.) But I definitely notice effects on my internal experience from the brighter variants of the ordinary LED bulbs that most of us have in our homes, and the quality of those effects differ drastically from the quality of the effects from sunlight, which causes me to conclude that the UV fraction of sunlight is in expectation the cause of most of the positive benefit I get from sunlight exposure.
Specifically, within only a few seconds of the start of exposure to bright LED light, I am more alert, maybe it is easier for me to pay a certain kind of attention or focus and on a minute-by-minute basis, it becomes easier (requires less willpower) to turn intentions into sequences of actions. Sunlight has the same (almost instantaneous) effect, but also has other effects that LED light bulb light does not cause. In particular, the effect I value the most persists for hours after the end of the exposure to the sunlight and might persist well into the next day. A kind of optimism and bias for action, but very steady. also, the quality of my cognition seems to be better (in hard to describe ways) on a day when I get 20 or 30 minutes of late-morning or mid-day sunlight and use only the intensity of LED light needed to see comfortably than on a day when I get little or no sunlight, but spend the day under LED light of the intensity one would find in an average office or store (i.e., much more LED light than I tend to use when I am in my home).
There is a lot more I could say on the subject (e.g., on mechanisms) but the essence is that there is a fuzzy argument relying heavily on subjective evidence for benefits (mainly mental) of high expected value from my moderate UV exposure and a very crisp argument, the soundness of which I do not doubt at all, compiled by dermatology researchers and ophthamology researchers, for pernicious harms (namely, melanoma and horrible eye diseases) of low expected magnitude, and I judge that the former easily trumps the latter because I trust my ability to evaluate fuzzy arguments (i.e., to avoid being systematically biased by, e.g., motivated stopping, motivated continuing or confirmation bias).
The expected benefit of my UV exposure is high because it is almost certain that various (mostly mental) benefits are being manifested and because even though I cannot be precise in describing those benefits or in evaluating the (personal) utility of those benefits, the utility is quite significant in magnitude. The expected harm of my UV exposure is low in comparison because the probability of the most pernicious harms (melanomia, etc) is (as you note) low.
Thank you for that. I tentatively accept your assertion that the British study (summarized by the Youtube video I referenced) is not credible.
For science, I wrapped my body in a polyester blanket and wore a sun hat with UPF of 50+ and sunglasses so that none of my skin was getting UV at any significant intensity and spent half an hour in the mid-day sun. All sunglasses on the market from name brands reliably block UV. Polyester is very effective at blocking UV and like almost all fabrics will let at least half of the photons at most infrared wavelengths through. I did this prol at least 20 times. This protocol might have had some positive effect, but if so, the effect went unnoticed by the methods I used (namely, mere introspection and curiosity) or the effect was not large enough for me to be sure that the effect is actually there. In contrast, 20 minutes of mid-day sunlight on a cloudless day on my bare skin and into my “bare” eyes has a pronounced positive effect which are obvious to me.
(Also I once had a session in a machine that costs many 1000s of dollars that I climbed into naked that bathed me in all directions with red light and near-infrared light produced by thousands of LEDs. I did not notice the effects that I value the most from sunlight exposure.)
That strongly suggests that some combination of visible light and UV light is the cause of the effects I value the most. Here let us observe that the common LED light bulb produces no UV light.
I’ve never made the experiment as far as I can recall of exposing myself to LED light bulb light that is as intense in the visible spectrum as the mid-day sun is. (Frankly I would probably strongly dislike the experience.) But I definitely notice effects on my internal experience from the brighter variants of the ordinary LED bulbs that most of us have in our homes, and the quality of those effects differ drastically from the quality of the effects from sunlight, which causes me to conclude that the UV fraction of sunlight is in expectation the cause of most of the positive benefit I get from sunlight exposure.
Specifically, within only a few seconds of the start of exposure to bright LED light, I am more alert, maybe it is easier for me to pay a certain kind of attention or focus and on a minute-by-minute basis, it becomes easier (requires less willpower) to turn intentions into sequences of actions. Sunlight has the same (almost instantaneous) effect, but also has other effects that LED light bulb light does not cause. In particular, the effect I value the most persists for hours after the end of the exposure to the sunlight and might persist well into the next day. A kind of optimism and bias for action, but very steady. also, the quality of my cognition seems to be better (in hard to describe ways) on a day when I get 20 or 30 minutes of late-morning or mid-day sunlight and use only the intensity of LED light needed to see comfortably than on a day when I get little or no sunlight, but spend the day under LED light of the intensity one would find in an average office or store (i.e., much more LED light than I tend to use when I am in my home).
There is a lot more I could say on the subject (e.g., on mechanisms) but the essence is that there is a fuzzy argument relying heavily on subjective evidence for benefits (mainly mental) of high expected value from my moderate UV exposure and a very crisp argument, the soundness of which I do not doubt at all, compiled by dermatology researchers and ophthamology researchers, for pernicious harms (namely, melanoma and horrible eye diseases) of low expected magnitude, and I judge that the former easily trumps the latter because I trust my ability to evaluate fuzzy arguments (i.e., to avoid being systematically biased by, e.g., motivated stopping, motivated continuing or confirmation bias).
The expected benefit of my UV exposure is high because it is almost certain that various (mostly mental) benefits are being manifested and because even though I cannot be precise in describing those benefits or in evaluating the (personal) utility of those benefits, the utility is quite significant in magnitude. The expected harm of my UV exposure is low in comparison because the probability of the most pernicious harms (melanomia, etc) is (as you note) low.