Recently I found this note on my desk at home. It says “I HAVE NO IDEA
WHAT I’M DOING”. I don’t remember writing it, but it was in my house
on my desk in my handwriting, so I obviously did.

He might want to seek some psychiatric help if this persists.

So what did it mean? Was it a cry for help? A product idea? A topic
for a blog post? Or could it be an idea for a conference talk?

The card was a cry for help. This talk is a cry for attention.

I’ll begin by showing you some compelling evidence that I have no idea
what I’m doing.

Well, he definitely proved it with all the completely asinine comparisons in the rest of his talk, but this one is the best:

If you only take one thing away from this talk, make it this: beavers are
idiots. They have no idea why they’re building these huge structures; they just
blindly do it.

Really.

"One of the primary reasons beavers build dams is to surround their lodge with water for protection from predators." [...] "On land, the beaver's short legs and wide body made them slow and vulnerable to their enemies. However, unlike most of their historic predators, beavers are excellent swimmers. As a result beavers evolved to have a strong preference to remain in or very close to the safety of the water. The need for safety is the primary reason beavers build dams to create ponds." -- http://www.beaversolutions.com/about_beaver_biology.asp

Sounds like they have a pretty good idea why they build dams.

But enough about me. As you’ve seen, I frequently find myself in situations
where I don’t know what I’m doing, and I usually hit a brick wall and
feel disappointed. But it’s not just me! You have no idea what you’re doing
either.

Don't go projecting on us, buddy. Most people, when faced with a challenge they're not immediately sure how to solve, will go read a book, or take a class, or ask someone who does know what they're doing. Lying about being able to write a book when you have no idea how in order to make money is not "impostor syndrome", it's merely being an impostor.

Dunning-Kruger does not explain or justify a total lack of forethought.

All of these animals look remarkably like something in their environment,
but none of them has any meaningful understanding of why they look that way.
They don’t know what they’re imitating. The stick insect doesn’t know anything
about eucalyptus; that’s just what it looks like.

Says who? You, the expert? I'm pretty sure an animal who lives on a goddamn plant and looks just like it probably realizes that it's a plant, and that it looks similar, and that if it wants to eat, it should use that plant in order to hunt, so it can live.

An interviewer asked Richard Feynman to explain how magnetism works. He explained that it was a force that interacted with certain things. The interviewer asked, but why? Richard's answer was a long way of saying "just because, you moron."

You don't need to understand every layer of the onion. Every layer has another layer, and once you understand every single of them, and grok quantum physics and multiple dimensions and relativity and whatever else affects that onion's properties, that won't change that you need to cook that onion until it's soft before you add in meat to get the flavor out of it. If you know how to cook it, you know what you're doing.

It's not that the author has no idea what he's doing. He's just an idiot.