Exploring the Persistence of Memory: Sagan and the Legacy of Life

“Books are like seeds. They can lie dormant for centuries and then flourish in the most unfavorable soil.

In this episode, Carl Sagan invites us to reflect on the role of intelligence in evolution. Not as a mere biological tool, but as a cosmic inheritance. "The Persistence of Memory" explores how humans—and other life forms—store information: from genes to books, from neurons to computers.

It's a meditation on knowledge, its transmission, and its fragility. What does it mean to remember? How are ideas perpetuated? And what role does collective memory play in the fate of civilization?

A story of information

Carl starts with biology: DNA as the first major information storage system. Through it, life copies, transmits, and modifies data in an evolutionary dance that lasts billions of years.

But then the focus shifted: from genetic code to language, and from language to writing. Each advance not only preserved information, but also multiplied its reach and speed.

It shows us how the human mind has developed technologies—such as libraries, the printing press, and computers—that expand natural memory capacities. Thus, our history lives not only in our genes, but in the records we create.

Ilustración esquemática sobre almacenamiento y evolución de información

Brains, machines and civilization

The episode delves into the brain as a processing machine. It examines how memories are chemical imprints, synaptic connections, and how learning physically shapes the brain.

Sagan also anticipates what we call artificial intelligence today. Can machines think? Can memory exist without consciousness?

A civilization, he says, is only as strong as its capacity to learn from itself. Without memory, there is no science. Without history, there is no progress.

Warnings about forgetting

Sagan reminds us that all this accumulated knowledge is at risk: wars, censorship, intolerance, or the simple passage of time can destroy centuries of learning.

Just as the Library of Alexandria was reduced to ashes, our databases too can disappear if we don't take care of them.

Memory is not only biological or technological: it's also cultural. And as such, it requires commitment.

Cover of The Dragons of Eden: A book about the evolution of biological and neural intelligence

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Interesting curiosities

• The episode explains how genetic sequences preserve traces of common ancestors between species.

• The evolution of written language is illustrated, from clay tablets to digital codices.

• The human mind is compared to a computer: not to reduce us, but to better understand our cognitive functions.

• The fragility of storage media throughout history is highlighted.

Key themes of the episode:

• DNA as a primary information code.

• The evolution of cultural memory systems.

• The brain as a learning mechanism.

• The risk of losing accumulated knowledge.

• The role of learning in the survival of civilizations.

Final reflection

"The Persistence of Memory" is not an episode about the past, but about continuity. Sagan reminds us that knowledge is humanity's true heritage. It doesn't matter how much we've learned if we don't know how to preserve and transmit it.

Because, ultimately, to remember is to resist forgetting. And as long as a mind, a species, or a civilization can remember and learn, the universe will not be a silent place, but a self-aware one.

And so, between genes and galaxies, we conclude our journey through "The Persistence of Memory." Next week, we'll continue exploring the universe with Episode 12: "Galactic Encyclopedia . "

What place does humanity occupy in the vast cosmic archive?

See you very soon to find out.