Dear Media:
It's time you began calling out people who use "no one knows" to "justify" their acts. Despite appearances, "no one knows" is almost never an expression of modesty. Rather, it is a way to create a false equivalence between expertise and opinion, and to devalue reasoning itself.
Miscreants long have abused "No one knows" and its variants. For example, climate-change denialists often (falsely) say that we know little about climate, then leverage that propaganda to argue that we should do little to combat climate change.
More currently, some oppose COVID-19 restrictions by using phrases like "No one knows particularly the best strategy". [1] The fact is that we do know effective strategies, but they are economically injurious (in the short term) and politically distasteful. One such strategy is weeks-long shutdowns to suppress the virus enough for it to be contained by masking, distancing, and vigorous testing and contact tracing. [2] But, as with climate-change denialism, purveyors of "no one knows" don't like the necessary policy, so they attack the antecedent reasoning -- and, indeed, the power of reasoning itself.
The attack on reasoning is, in my view, even worse than the avoidance of vital policies. If we treat poppycock and woo as equal to rational inquiry, we attack the way of thinking that raised vast numbers of us from disease, squalor, slavery, and subjection; to relative health, security, and freedom, and to a much fairer way to determine our own destinies. [3]
It's our choice. We can choose the easy, false path and blame dream-demons' sperm and malicious doctors with space-alien DNA for our problems [4]. Or we can take thoughtful care to understand our challenges, and considered courage to fight them.
[1] GOP Iowa Gov. Kim Reynolds, quoted in Achenbach et al, "Some experts calling for total shutdown, as coronavirus threat rises across U.S.", https://www.washingtonpost.com/health/coronavirus-threat-rises-across-us-we-just-have-to-assume-the-monster-is-everywhere/2020/08/01/cdb505e0-d1d8-11ea-8c55-61e7fa5e82ab_story.html
[2] The shutdown reduces viral spread while infected people recover (or, alas, die). This radically cuts the number of people with active (spreadable) infections. Once there are few enough infections, the shutdown can cautiously be eased. Widespread masking and distancing then help suppress general spread, while vigorous testing (with quick results), contact-tracing, and quarantine help find infected people and help prevent them from spreading the virus.
[3] (And yet we still desperately need to become "more perfect", as the Preamble to the Constitution says.)
[4] I am not concocting this trash. A person claiming to be a "doctor", retweeted by Donald Trump and his son, claims, among other things, that dream-sex with demons causes uterine diseases, that doctors use space-alien DNA, and that hydroxychloroquine is an excellent remedy for COVID-19. See Andrews et al, "Stella Immanuel, a doctor in a viral video of false covid-19 claims, has said demons cause illnesses", https://www.washingtonpost.com/technology/2020/07/28/stella-immanuel-hydroxychloroquine-video-trump-americas-frontline-doctors/ .