Sure, but there's also a question of bootstrapping. Can you build electronics that work underwater? Sure. But it's a lot harder than building electronics that work on land. The barrier is a lot higher.
Also, simple things like... Primitive humans used tree branches to build lances and things to fight predators. They also used them to dig and to build homes. There are no trees underwater. Octopuses have soft bodies and are not equipped for digging in the ways that humans were, especially without tree branches to help them.
Another obvious difference: one of the key technological discoveries that made humanity happen is the discovery of fire. It would be somewhat difficult to make fire underwater.
Maybe it really is just easier on land. That being said, many species have gone from sea to land or land to sea during their evolution. Not impossible that some octopus descendant could become a land species in the far future... But I have a feeling that evolving bones or a hard shell would he helpful there.
cue movie scene where an octopus, drawn by strange unheard noises, surfaces and witnesses nuclear bombs exploding just above the New York skyline from far away, and the dawn of a new era begins
I'm wavering over the two perspectives here. It does make sense that a water environment places far too many barriers on all sorts of natural processes, chemical, & physical, that seem necessary for any sort of technology. On the other hand we do have another form of "terra-"centric bias here, this time regarding the 'alien' -- the essense of the question considered imo -- environment and its alien creatures. So maybe there are in fact possibility spaces and progressive trajectories for 'high technology and science' via entirely novel takes on environmental manipulation. So, sure, no fire under water, but they have electricity [and light sources] (!!) on tap. Maybe Octopus sages will hit on 'eletricity' before 'fire'. Maybe they will learn to farm and control large collections of eels to power stuff [or build logic gates ..]. Maybe they will develop PSI powers (a bit woo) but who knows.
p.s. turns out in fact they do use other creatures as 'tools':
These guys need to first figure out how to store and convey information. I think this is their biggest obstacle. Whales possibly convey transgenerational knowledge via songs. They need something like that. We humans could possibly assist them in this by placing devices in their environment that could help them get over that hump. They apparently have sense of smell, so maybe something using chemicals for an alphabet, or pictograms. Since they have great visual processing, a combo of chemically coated (from a finite set of smells) image tokens with distinct images (from a finite set of diagrams) could work and possibly convey complex ideas (c x i basic semantic units).
Underwater is much older. So no chance it hasn’t already happened.
My theory is Octopus became intelligent long ago, but that civilization kept killing itself off (ennui, nukes, whatever) and that’s why now they live alone and kill the selves after breeding. Only stable intelligent offshoot to survive.
I probably didn't explain myself very well, but I do mean improvisational and long term. I haven't seen 2 year olds plan more than like a minute ahead, and they definitely need to be taught how to manipulate even the most basic objects (beyond simply putting the thing in their mouth). A four year old human certainly does those things, but the comparison is with octopuses, whose typical lifespan is less than 4 years.
Long term planning would be surprising, I agree. But what about carrying around a teddy bear? Sure, not a tool but of utility (comforting) to the child. Maybe it's just that. It had it around once and found it useful, and became 'attached' to it.
But, these guys have a sort of ensemble distributed processing system which is pretty cool. (We do too. The feeling in the 'gut' is thanks to ganglia.) Specialized processors have less to learn and learn faster, maybe?
"Every time they eat, they risk severe brain damage if their meal isn’t well and truly chewed up! Luckily they accomplish this by slicing up their prey with their serrated radula plus breaking down their meal with enzymes in their saliva."
Evolution or God was watching out for us terrans. Looks like they have a built in fail-safe switch to keep them from ever growing bigger or getting bigger brains. /g
I guess it is more habitation than toolusage, which is more common in nature, so its not as interesting however some of the constructions are really elaborate planned and beautiful in their own right, its truly fascinating.
