Let’s ask you…

Would it still be you if we erased your memories?

What if we cut off your head and put it in one jar and your body in another and keep you both alive. What jar would you say you are in?

What if we split all your cells and then rebuilt you cell by cell… would it be you again?

No excuse for questions being abrupt, but we’ll try to get used to it. a slippery and deceptive concept: our sense of identity.

What are you but your body?

Where are you in your body and how much can we do to your body? Is your core self non-stop?

To help us with these complex questions, we turned to one of the simplest creatures on the planet: the sponge.

“They are often defined by what they don’t have. “People don’t understand how they manage to do anything with so little,” says marine biologist Sally Leys, Professor of Biological Sciences at the University of Alberta, who specializes in sponges.

These aquifer animals, which have existed for about 5 to 8 million years, are essentially giant tubes that filter water.

They have no muscles, no organs, no nervous systems, no brains, so you can assume they have no thoughts, feelings, and self-awareness.

However, they can do something great…

From cloud to sponge

(The laboratory experiment below is brutal, but not deadly, as it allows scientists to study various aspects of animal biology and also provides insight into how early organisms formed.)

“If you take a sponge and run it through a very small mesh size – 20 microns more or less – there are some cells that connect and slowly organize themselves by moving and colliding. to rebuild the whole body »says the expert.

Sponges can actually do just that: regroup from some kind of living slime on the seafloor.

It’s like a superpower.

The classic experiment—says Leys—is done with a blue and red sponge, which, after passing through the mesh, turns into a purple cloud of cells under the right conditions and given enough time (from a week to 10 days). they transform and remodel into a blue sponge and … (you guessed it) a red sponge.

“Well they have the ability to determine the self from the non-me”.

million dollar question

It is worth repeating: They can determine the self from the non-me.

They have a kind of self-awareness that is encoded directly into their individual cells.

Genetically, the reassembled sponge is the same as the decomposed sponge.

But the million dollar question if the regenerated sponge is the same sponge or if a new animal has become pregnant within these 10 daysa clone created from a nonexistent clone.

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It’s hard to say.

It depends on how much of your memories, personality, and other things that we thought constituted the self, passed from the original sponge to the reconstructed sponge.

But wait, we just determined that sponges don’t have brains… so they shouldn’t have personalities or memories, right?

Another great thing about sponges is this: In a way, they do.

“You can actually see that there are things that bother them,” Leys explains.

Why does the sponge get irritated?

“He’s uncomfortable with movement, so if you knock on the table he’ll feel the vibrations and spit out what we call a sneeze.”

“It takes about an hour to relax again. So basically you have to do something else until the anger subsides.”

“Sometimes students postpone experiments because If you do it in the morning, some sponges will be upset”.

“We learn to learn about their characters by working with them in the labs.”

And them can they learn thing?

“In the sense that they can recognize a situation they’ve encountered before, it’s possible.”

Leys describes how he once managed to train a sponge to stick to Petri dishes the way he wanted.

At first, it would shrink like a ball and it would open, but then it would back up and it would open.

“On day five it started doing exactly what I wanted so they could learn and adapt in situations like this.”

and will it remember what you learned after it disintegrated and reintegrated?

“Good question! The populations we study have learned traits. They have adapted to freshwater, for example, by performing regeneration processes».

“The question is how many times you can take a sponge and reduce it to cells, allowing them to recombine without stopping as they were before.”

And that brings us to the beginning: our self-awareness.

Already teleportation paradox.

Star wars?

Yes, we’re talking about traveling at the speed of light between galaxies at the touch of a button.

Ever since science fiction began toying with the possibility of teleportation in the late 19th century, the idea has puzzled philosophers such as Charlie Huenemann of Utah State University in the USA.

“I’m stranded on Mars. The fuel tanks on my return ship exploded and no rescue team can come to my rescue.”

“But luckily my ship has a teleporter. The machine scans my body and produces an incredibly detailed blueprint, a clear view of every cell and every neuron, which is then transmitted back to Earth where a new self is built using available raw materials.”

It sounds good: salvation is at hand… or rather the finger pressing the button. What is the problem?.

“I can rationally understand why this should work, because I’m just a certain cell configuration, and a carbon molecule is no more like me than another carbon molecule. As long as everything is arranged the same way, it shouldn’t matter,” agrees the philosopher.

But it’s not that simple.

Note that this is a paradox, so it raises a question: the machine, Does it transport you to the other end of the Universe or does it kill you? and all your memories and personality intact creates a new version of you on Earth, who does he think you are?

“I think I would die on the transporter on Mars and someone very similar to me would appear on Earth.”

“It would have had all the cellular structure, all the neural connections, etc. to think it was me, and it’s not clear that my copy on Earth is wrong.”

“Anything that made me think it was me would be found in that replica on Earth.”

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But if your memories, your molecular and neural structure are yours and everything is a carbon copy, why not you?

“That’s what I find very interesting about this thought experiment.”

“What he taught us is, in a deep sense, there is no self as an indivisible unit Whether he could make this leap from Mars to Earth.

In other words, this self-awareness – ‘I know I am’ – is actually an illusion.

Indeed, many philosophers have called it the self. ‘user illusion’. An affordable illusion originating in our life. ‘I feel like I am the person I was yesterday and I hope to be the same person tomorrow’.

“But if we try to go further and ask ourselves, ‘Is there a permanent self that stays the same over time?’ If we ask, then a thought experiment like the teleporter teaches us: no, it doesn’t exist.”

Identity crisis

So even if you feel like you are the same person as yesterday, things are different: the weather, the food, the people you interact with, the way you do it, your mood…

Maybe what you are is a repeat of yesterday, not exactly the same person.

plus what makes you not just who you are -the arrangement of your atoms, your genetics, or what’s encoded in your cells- but also where are you.

Huenemann says, “Most of who we are is made up of our relationships with other people: the society you live in, the job you have, etc.”

Before you go, another thought experiment without having to leave the planet.

When you go to bed tonight, you will lie down, you will hug and then you will pass out. And when you become unconscious, your awareness of yourself will somehow dissolve.

While you sleep, your body and brain will transform. Many of your cells will change and you can wake up with new neural pathways.

Is ‘you’ waking up in the morning the same as ‘you’ sleeping the night before?

Maybe yes or maybe no: it is possible to rearrange the illusion of self every morning.

There is no way to know…

* This article is based on the episode “Sea-Sponges and the Illusion of Self” of the BBC series NatureBang. Click here if you want to listen.