I think there's more nuance to that. Not all truths are as easily proven as 2+2=4. Usually an echo chamber is only considered as such when the people parroting

I think there's more nuance to that. Not all truths are as easily proven as 2+2=4. Usually an echo chamber is only considered as such when the people parroting a "fact" do so with confidence that far exceeds any proof that they can provide. The mask issue GP brings up is a great example. Before the COVID-19 outbreak most people generally regarded the practice of wearing face masks in Asia with scorn. If you asked them about it they would invariably bring up the same fact that "virii are too small and will pass through the mask". However, very few would be able to cite sources, and even fewer then would have an accurate enough understanding of how virii spread to know that most of the time the virus is a part of a much larger particle[1][2] that masks are effective at preventing to some extant[3]. It's not surprising that most people wouldn't have a perfect understanding of epidemiology, but it does become suspicious when a large group of people all become overconfidently wrong in exactly the same way. This is what I would consider to be an echo chamber. [1] https://www.cdc.gov/coronavirus/2019-ncov/prepare/transmission.html https://www.cdc.gov/coronavirus/2019-ncov/prepare/transmissi... This source confirms that coronavirus spreads via droplet. [2] https://www.who.int/csr/resources/publications/drugresist/WHO_CDS_CSR_EPH_2002_12/en/ https://www.who.int/csr/resources/publications/drugresist/WH... This source defines "droplet as being particles greater than μm in diameter on page 44. [3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440799/#!po=35.9375 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440799/#!po=35... This article measures a protection factor of ~4 for a surgical mask when measuring with a detector that detects particles ranging from 0.02 to 1㎛.