This looks to me to be a case of a Not Even Wrong level of being wrong. Darwin appeared to be - usually - a very good observer but I have an image in my mind of him swiping and swatting unthinkingly at annoying flies as he wrote that, without noticing that he was reacting to the disturbance of highly sensitive hairs - that the principle way he was feeling them (very annoying) was hairs, not skin. Note I am not that interested in dumping on Darwin - but he didn't get everything right and did get this wrong. I am more inclined to dump on the very many academics that came after, who sought to understand the evolution of furlessness in humans, who (like Darwin) lived their lives immersed in the sensations hairs provide but never noticed! Which makes another question - how it is possible anyone could not notice, let alone someone who set out to understand how we evolved the patterns of hair growth we do. Or else they didn't want to question Darwin's (sort of) claim that body hairs are useless? The evolution of human furlessness (usually, misleadingly, "hairlessness") has been a long running interest of mine, arising initially from a "that isn't right" reaction to the claim that human body hair serves no useful purpose. I had (then) recently felt a tick (an Australian Paralysis Tick - nasty things) walking up my leg, because it bumped against the hairs. Avoiding just one bite by one of those makes having hairy legs worthwhile. The sensory function of those hairs alerted me to it's presence, before it had dug in. Not an absolute preventative of course; I spend a lot of time with my attention elsewhere and ignoring "ordinary" sensations is more usual than paying close attention to them. But it did prompt me to observe more closely - to notice that a fly or small ant walking around on my hand could be easily felt when it walked across hairs yet barely or not felt at all when it was on hairless skin. It wasn't that no-one had noticed that we feel things via our hairs, even during Darwin's time. But somehow it kept being overlooked, over and over. It managed to rate not even a mention in very nearly all published papers on how our "hairlessness" evolved, with assumptions of no function commonplace; their efforts were purely in explaining absence of hairs (sometimes erroneously assuming actual loss of follicles rather than just smaller hairs). If you don't know what hairs do for modern humans, how can it be possible to understand how and why they evolved that way?