Augustus
…
I had the same thought.
I would say the mental process goes something like: I scan the sentence (about the invisible truck) to determine its meaning. I hit the word "invisible" and that triggers a definition that includes "invisible is non existent" and then my judgment becomes "the claim is false".
There is so much information presented to us all the time that we store pre-processed answers to a lot of things, so we don't have to actually evaluate them again. That doesn't mean that at some time we didn't think enough about "invisible' to decide that it is not possible.
I agree in general. We automate responses to save effort with things we are familiar with. We don't need to calculate 2+2=5 to know it's wrong, and a mechanic might be able to tell you what is wrong with your car based on the sound it makes as you drive in. We have to learn these initially, but they become automated with repetition.
We are also biased towards assuming things said to us make sense though, which adds another layer.
So if someone says "watch out for the invisible truck" then I'd probably think it was a truck with the logo of a company called "Invisible", or perhaps that it was hyperbole and the truck was hard to see in the light, or even that it was a joke and there was just an army truck with camo paint so "we couldn't see it".
And when you get a nonsense sentence like "colourless green ideas sleep furiously" it actually requires more cognitive effort to process than something than needs to be responded to like "can you pass the salt, please" as the collocations are uncommon.