[1]: http://www.annualreviews.org/doi/abs/10.1146/annurev.psych.5...
[2]: http://onlinelibrary.wiley.com/doi/10.1002/jclp.20129/full
When I lived such a winter, the effect of standing in full sunlight when it was available was like eating sugar after heavy exercise. (And biochemically, this makes perfect sense given that we know the body uses sunlight to synthesize essential compounds.)
It makes sense to question the effect of a specific lamp, but the body's need for sunlight is obvious, even absent the scientific research.
person 1: Aliens have visited our city.
person 2: Is there proof of that?
Probably just an optical illusion or something.
person 1: Can you prove aliens didn't visit?
What is your math for optical illusion?
I'm sorry, but the burden of proof lies with the person making a claim, not with detractors.Also, when people assert that UFOs are probably just an optical illusion, they are (or at least should be) doing that based on the long observational baseline of many investigated incidents which indeed turn out to be optical illusions. That is to say, it's legitimate to say that perceived UFOs are probably optical illusions it's because there's real data demonstrating that perceived UFOs really are optical illusions.
The illegitimate version of that would be saying it based on general arrogance, which is frequently a barrier to scientific progress. See, e.g., the story of Nobel Prize winner Barry Marshall.
Further, your request is nearly tautological. The way that one gets to a big, statistically robust test of a hypothesis is via small stepping stones. E.g., this sort of self-experimentation. If you scoff at everybody doing something small and say, "you're probably wrong because there's no big evidence", you decrease the chances of getting the sort of proof that you claim to want.
I don't think there's anything wrong with saying, "personally, I'd like to see convincing measures of the effect of bright light therapy on mood and intelligence before I adopt this." But that's frustratingly different than your apparent attitude that in 2 minutes of thought you know more about this guy's experience than he does.