Charles Darwin might be known for his meticulous and brilliant scientific mind, but what is less known is that he was also prone to bouts of moodiness. In fact, in letters written to his friend, Charles Lyell, which were recently released by the American Philosophical Society, the father of evolutionary theory sounds downright pouty, reports NPR.


Darwin's 'emo' leanings are on full display in the letters, as he expresses self-doubt, misanthropy and general peevishness. Take for exhibit A this gem, written in a letter marked for Oct. 1, 1861:


"I am very poorly today and very stupid and hate everybody."

Who knew he had it in him?! The poor old man was clearly not having a good day. The letter goes on to discuss a book on orchids that he was writing at the time, though Darwin quickly makes it clear that not even flowers could cheer him up on this day:


"I am going to write a little Book for Murray on orchids, and today I hate them worse than everything."

To put the words in context, keep in mind that these letters were written two years after the publication of his magnum opus, "On the Origin of Species." So Darwin's insecurities could not have come from a lack of accomplishment. He was just staight-up being a cranky-pants.


To be fair, Darwin's years of work on "On the Origin of Species" took a toll on him. Unlike how geniuses are often imagined, ideas did not come easily for Darwin. It took decades of ironing out the kinks, toiling over the words, and piecing together the evidence before he felt confident in his work. For instance, "On the Origin" was not published until 23 years after he returned from his epic journey on the HMS Beagle. If Darwin was brilliant at anything, it might just have been thoroughness.


In fact, perhaps what we're seeing in these letters is exactly what prompted Darwin to be so meticulous in the first place. Perhaps it was his brooding lack of self-confidence and general distrust of others that made him so diligent.


"One lives only to make blunders," he goes on to write to Lyell.


It's easy to feel sorry for Darwin, who also had to deal with years of ill health, including a weak heart and a chronically upset stomach. But it's difficult not to feel sympathetic for his poor friend Lyell, too. Lyell was himself one of history's most important scientists, the preeminent geologist of his day. Lyell's own great work, "Principles of Geology," was a major influence on Darwin's theory of natural selection.


Now that we know about the groveling he had to put up with from his dear friend Charles Darwin, perhaps Lyell should also get some credit as a psychologist.