At the risk of badly mangling things smarter people have probably already worked out 1 over seven plus decades and counting of the ongoing computer revolution 2, here goes.
Category One: Memory Assistant
I'd box all the note taking tools in here—as persistent store and/or organiser and/or search tools. As a user of such a tool, all meaning-making is the job of my brain. I must work out the known unknowns, deal with the unknown unknowns when they happen etc.
The tool functions like a mechanical memory + ontology + topology assist, which helps me do a lot of thinking + learning over long periods of time (like days, weeks, years). Things like Ken Iverson's concept of Notation as a Tool of Thought 3 would also fall into this category (filed under "methods to compress information into symbols and mnemonics and transmit them").
Hell, why be so fancy? I dump it all into my haphazardly organised org files and rgrep and its going… fine?
🤷♂️
Category Two: Co-processor
Two intellects working together to arrive at a common model / picture / frame of understanding. People on the Internet and in my familiar circle of gentlenerds seem to be excited about CoPilot / ChatGPT etc. in this sense.
I can't help but see those as just more of Category One type tools. Why? Because co-processors must be capable of communicating understanding of abstract models with each other (a kind of "Communicating with Aliens" 4 problem). AFAIK, none of these tools are capable of explaining why they're doing what they're doing.
The one exception I could concede to is machines that are excellent at finite games. That too because odds are higher of being able to independently verify the machine's meta descriptions, and the outcomes would be reasonably reproducible (viz. "I did X, because of heuristic Y, and rules P, Q, R.").
Category Three: Teacher
One intelligence absorbing greater truths discovered by (or previously absorbed by) another intelligence. Where the other intelligence has the metacognition to know what they know, and to direct the other intelligence to that level of understanding. The magic of beings capable of transferring culture, stories, Laplace transforms, rate reaction equations, rules of grammar, interpretation of law etc. across minds, and generations.
I'm thinking tribes, coaches, mathematics circles, therapists, the Vulcan Science Academy and so forth… the ability to conjure up and communicate about concepts like communicating with aliens.
AFAIK, only biology is capable of producing this category of tools of thought.
In this context, I'm fascinated by the work being done on Bioelectric Networks by Michael Levin's group 5. Almost prosaically, in their work/world the definition of intelligence is a mechanical one. So much so that they are able to model and then produce (though not control or guarantee) biological structures capable of progressively more sophisticated kinds of intelligence in the mechanical terms they describe.
Which makes me wonder…
Is there something like the Kardashev Scale 6, but for levels/depths/spans of Intelligence?