Could a human level intelligence species evolve in the oceans?

I know dolphins are pretty intelligent as far as other animals go. But even they are a far cry from human level intelligence. Do you think there are any limiting factors that would prevent human level intellectual evolution in the oceans?

Did you watch, “Mermaids, The Evidence Found” ?

The best factual answer is “we don’t know, because we don’t have enough data points”. There’s a lot of well (or ill-) informed speculation that can be done, that may be of interest, but the only solid data we have to go on is humanity and our relatives here on this one planet, and that’s just not enough to tell us what is and is not possible out there in the wider universe.

I’ve thought that a key to human’s advanced development (and a reason why whales and dolphins don’t seem as advanced) is the dexterity of man’s fingers: brain evolved to support the difficult tasks fingers can perform.

In this connection, the dextrous octopus – called the most intelligent invertebrate – comes to mind. Another SDMB thread linked to Youtubes of octopi doing amazing things. (Of course the octopus isn’t anywhere comparable to human in intelligence, but it does suggest an answer to OP’s “could” question.)

Short answer: no. What we call ‘intelligence’ is tailored to terrestrial existence.

That’s correct: Human higher intelligence must necessarily have evolved more-or-less in step with advanced human ability to manipulate the environment, which meant hands, fingers, opposable thumbs, inventing atomic bombs and New York, etc. It’s a tenet of evolutionary theory that unused capacities will devolve (that is, de-evolve) through lack of use. For example, species of dolphins that live in muddy rivers have become blind. Similarly, the physical ability to make very articulate and varied sounds, i.e., the ability to talk, must have evolved concurrently with the ability to understand and use language. (There are different theories of why parrots can talk: I think the ability to imitate sounds developed as a mating strategy that got carried away.)

Bottlenosed dolphins are thought by some to have intelligence equal to, or even exceeding, human intelligence. This is consistent with the opposable thumbs they have developed. They have already learned how to train humans to do tricks for their amusement, such as feeding them fish (as documented by Karen Pryor, former head trainer at Sea Life Park, Honolulu, in Lads Before The Wind, Chapter 1).

Next thing you know, we’ll be thanking them for all the fish.

I would agree that something very dexterous like an octopus has the best possibility. I think another requirement is the ability to develop a complex language capable of describing abstract concepts. I suppose octopi could use their chromatophores for this purpose. I think one huge hurdle is going to be the development of written language. I suppose you could carve coral.

No, it’s not.

Having a written language isn’t necessary for “human level intelligence”. We lived 90% of our existence as a species without it. But water needn’t be an impediment to that.

Short answer: no. What we call ‘intelligence’ is tailored to terrestrial existence.

Yes, it is. We can do things that sea creatures cannot, and vice versa. But what makes us ‘intelligent’ as we define it includes things that are not possible for sea creatures.

Like what?

Even if we accept that as true, we can easily argue that it’s a shortcoming in our definition, which is based, as I said, on a single data point, rather than an inherent limitation in evolutionary possibility.

Gotta disagree. Literacy is critical to absorbing knowledge and passing it on. A huge reason we’re not still living in caves is the development of language allowing us to learn from our ancestors. While oral tradition is somewhat effective it pales in comparison to literacy in it’s ability to transfer, maintain, and update knowledge.

You disagree that we had “human intelligence” without a written language for 190,000 years? That’s a fact, not an opinion.

Perhaps you are thinking of “civilization”, but that’s not what the OP asked.

Actually, yes.
I believe there is a nurture aspect to intelligence as well as a nature aspect.
It’s clear that children who are neglected and do not develop strong language skills and literacy have significant difficulty developing them later in life. These people lose a good deal of the potential they had.
I posit that if you took twins and one was raised in a, educational and challenging environment and the other was severely neglected and denied the opportunity to learn that they would have vastly differing intelligence by any measurable means.

Can you cite the written language that existed more than 10,000 years ago?

What does that have to do with the OP?

absolutely not.

It’s both, of course, as a little reflection will reveal to you. But not a ‘shortcoming’ as such, but rather a specificity.

Well the OP asked about the ability to develop human level intelligence. I stated that I believe written language is a requirement.
You disagreed, I replied to you.

There are literally millions of people alive who have no access to written language and no one can objectively say they don’t have “human level of intelligence”.

But more importantly, I want to hear about the written language that humans used for their first 190,000 years of existence as a species.

Not by any definition of “intelligence” I have ever encountered. What are these things we can do that you think are criterial for intelligence, but impossible to do under water? You have yet to provide a single example.