“You can’t evict an idea” was a slogan used by the Occupy Wall Street movement in November 2011; although the occupiers were evicted, their ideas were to remain. “You can’t evict an idea” was also a slogan used in Amsterdam in 2007.
 
A similar saying is “Ideas are bulletproof” (“You can kill a man, but you cannot kill an idea”).
       
 
Wikipedia: Occupy Wall Street
Occupy Wall Street is the original protest that began the worldwide movement beginning September 17, 2011 in Zuccotti Park, located in New York City’s Wall Street financial district, initiated by the Canadian activist group Adbusters. The protests are against social and economic inequality, high unemployment, greed, as well as corruption and the undue influence of corporations on government—particularly from the financial services sector. The protesters’ slogan We are the 99% refers to the growing income and wealth inequality in the U.S. between the wealthiest 1% and the rest of the population. The protests in New York City have sparked similar Occupy protests and movements around the world.
           
The Observer (UK)
Dutch squatters facing eviction in anti-liberal backlash
Jason Burke in Amsterdam
The Observer, Saturday 13 January 2007
(...)
As coalition talks continued last week, Holland’s estimated 50,000 squatters remained defiant. On a battered house near Amsterdam’s central station, squatters recently thrown out by police have slung a banner: ‘You can’t evict an idea.’
       
Prairie Dog Magazine (Regina, Saskatchewan)
Wednesday, November 9, 2011 3:48:11 PM
Octopi Regina – Day 26 Occupy City Hall
by Charles Atlas Sheppard
(...)   
“You cannot evict an idea. The Occupy Regina movement and this movement goes beyond the city park. It is in the hearts and minds of people who are suffering everywhere and around the world. We will not stop and nor will we bend. We will continue this movement for as long as people suffer…” promised activist Ras Munyaga.
 
WNYC News Blog 
Judge Rules Protesters Cannot Camp in Zuccotti Park
Tuesday, November 15, 2011 - 02:40 AM
By Arun Venugopal / Stephen Nessen / Bob Hennelly
(...)
Demonstrators said despite the setback, they planned to carry on their message protesting corporate greed and economic inequality. “This is much bigger than a square plaza in downtown Manhattan,” said Hans Shan, an organizer who was working with churches to find places for protesters to sleep. “You can’t evict an idea whose time has come.”
 
New York (NY) Times
London Protesters Warily Watch New York
By JOHN F. BURNS
Published: November 15, 2011
(...)
After a meeting on the cathedral’s steps of the free-for-all governing body for the London protest, a group of Americans from the encampment took the subway to Grosvenor Square, site of the American Embassy. There, flourishing their passports, the Americans unfurled a banner that read “They cannot evict an idea.”
 
New York (NY) Times—City Room
November 23, 2011, 2:04 pm
New School Is Squeezed Between Landlord and Occupiers
By AIDAN GARDINER
(...)
“We have hoped from the beginning that this occupation would only be the beginning, and that it would spread to other campuses and institutions,” Mr. Boscov-Ellen said. “As the Occupy Wall Street folks put it, you cannot evict an idea whose time has come.”
 
New York (NY) Times
Camps Are Cleared, but ‘99 Percent’ Still Occupies the Lexicon
By BRIAN STELTER
Published: November 30, 2011
(...)
As they lost physical ground for their local movements, protesters told each other online, “You can’t evict an idea.”
 
Google Books
Occupying Wall Street:
The inside story of an action that changed America
By Writers for the 99%.
New York, NY: OR Books
2011
Pg. 194:
As the protesters declared in face of Bloomberg’s second eviction, “You can’t evict an idea.”
 
Google Books
Occupy!:
Scenes from occupied America
By Keith Gessen; et al
London: Verso
2012
Pg. VII:
in response to these attacks, occupiers posted a message online. “You can’t evict an idea whose time has come,” it began.
 
Salon.com
Sunday, Jan 8, 2012 11:00 AM 21:56:00 CST
What Occupy can learn from the Hunger Games
A leaderless political movement still trying to find its place might look to heroes of dystopian fiction for ideas
By MIKE DOHERTY
“YOU CAN’T EVICT AN IDEA,” proclaim the banners fronting an otherwise dull building in east London, owned by banking giant UBS but inhabited and decorated by squatters from the Occupy movement. They’ve adapted the phrase from Alan Moore and David Lloyd’s graphic novel “V for Vendetta,” in which the titular terrorist explains his seeming immortality to a detective who has just shot him: “Ideas are bulletproof.” A poster of V’s trademark Guy Fawkes mask smiles eerily at all who walk into the foyer of 8 Sun Street, now dubbed “The Bank of Ideas” and used as a community center. The caption underneath reads, “We are the 99%, and so are you.”