[Antonello]

An interesting assertion, but for it to be so it would have to follow that species with greater memory capacity are more successful at survival. That would tend to form an inverted pyramid of life with those having the best memory forming the top layer and so on. Such is not the case.

Comparing the nautilus and squid, why is one having less memory than the other a handicap if both survive and are successful?

Short answer:
A species doesn't have to be as successful as possible, or even very successful. It just has to be successful enough to propagate the next generation.

Longer answer:
Brains take energy. The higher the capacity the brain, the more energy it uses. In some cases, a larger brain would consume more energy than it is worth, resulting in a shortage of energy for other, more useful traits. Natural selection doesn't care about the strongest, the smartest, or the fastest. It cares about the fittest for a given situation. If a more developed brain would give a population an edge in survival, then members of that population will likely pass this trait on in larger numbers than those members with a less developed brain. However, if that brain comes at the expense of a physical ability that makes a more necessary contribution to survival in the given environment, the brain will probably lose the evolutionary battle for dominance in the population's development.

Most species of life have little need for highly developed brains, and therefore expending energy on one would be a lethal luxury. Species that sacrifice energy for brainpower have a harder time finding niches to successfully fill. Therefore 'dumber' species that instead have developed other, specialized ways of survival vastly outnumber those whose physical abilities took a back seat to a big brain. On the other hand, brains come in very handy when the environment suffers a significant change. If those mindless, specialized critters lose their niches, they tend to die out and become extinct. A species that can learn another way to survive stands a better chance of at least surviving long enough to fill a newly created niche.

[count-your-change]

The longer answer sounds like what is called a just so story.
“Natural selection doesn’t care about the strongest, the smartest, or the fastest. It cares about the fittest for a given situation.”

You’re one funny guy. Natural selection can’t “care” or not care about anything.

And saying that if a thing is helpful it will be passed on but if it isn’t it won’t is the same logic that says we know it’s raining when water falls from the sky, etc.

Thanks anyway.