Not sure I understand the gist of the argument. First, let's separate "Intelligence Explosion" from "Singularity" as to many people those terms mean different

Not sure I understand the gist of the argument. First, let's separate "Intelligence Explosion" from "Singularity" as to many people those terms mean different things. A lot of the people talking about an "Intelligence Explosion" do not agree that the progress of science has been getting exponentially faster. What they are talking about, is that once we create an AI that can improve its own intelligence in a way that humans can't, then the improved intelligence will know how to further improve its own intelligence, and so on. Even if there is a limit to the number of discoveries possible in any field, if you're affecting the base rate at which you're making new discoveries, you can (potentially) continue making progress. More importantly, all of this is besides the point - it could easily be that all the "low hanging fruit" in improving intelligence can make an intelligence that is vastly more intelligent than a human, at which point the so-called "singularity" will have been reached. Or in the words of the "Intelligence Explosion" camp, we will have reached a world where we are no longer the dominant intelligence, possibly by a very wide gap. I see plenty of reason to think that human intelligence is not a good benchmark for "the maximum intelligence you can get by picking all the low-hanging fruit", since there are many, many easy improvements we can imagine that will almost certainly improve human intelligence (e.g., perfect memory, ability to partially reprogram yourself to do stuff, like for example not to have "bad" desires like eating unhealthily, etc.).