Mural Arts Philadelphia is in the midst of presenting a public art and history project called Monument Lab. The project, which runs through Nov. 19 and is co-curated by Paul Farber and Ken Lum, features the work of 20 artists in 10 locations around Philadelphia, as well as 20 events in and around the installations. On the eve of the city's dedication of a statue to civil rights hero Octavius Catto, some of the Monument Lab artists shared their thoughts about what makes a monument.

Tania Bruguera: As I thought about Philadelphia's great and long history of welcoming immigrants from all over the world, including those who arrived from other parts of the United States, such as freed slaves and the many African Americans who blessed the city during the Great Migration, I started to think about a monument in metaphorical terms. I thought about monuments as something representative of all the people, namely immigrants or people who have had to migrate, who have never been given a voice or were never listened to. A monument can express something heroic about humanity without having to be reduced to a single, identifiable hero.

Mel Chin: A monument is: a bipolar manifestation; based on an empire's artifact that has crumbled into dust; an opportunity for research; a gesture inadequate to express the complexity of loss, the gravity of sorrow; a tribute to the deserving; the reinforcement of myth; a refuge for imagination; to honor the fallen, to clue in the clueless; to mark the end of trauma; a mark of persistent trauma; a stimulus of hope; evidence of subjugation; wearing the mask of sentimentality under a veil of tyranny; a stand-in for beliefs that can be nurtured to drive murderous impulse; desperately needed to make sense of the senseless.

Kara Crombie: A monument is a community telling its future self what to remember. When it is good, it is visceral and created communally, compensating for the inadequacies of written histories.

Tyree Guyton: We are living in times where people are more concerned about things (i.e., statues, flags), and while it's true that they can evoke certain emotions, we believe that the greatest monuments are the ones living, and moving, and having their being in the world. Our hope, through our work, is to inspire the human monument (people) toward greater acts of courage that positively impact their own lives and the lives of others.

Duane Linklater: I think the definitions change and the meanings of who is being monumentalized shift over time, but perhaps it serves as some kind of material reminder of a past event or heroic person, something that the public as a whole should be continually reminded about. As an indigenous person who often visits the cities of North America, I am reminded of the violence endured by my ancestors, physical reminders of the violent colonization in North America manifested by statues of white men such as Christopher Columbus — but why should we be reminded of him? Why should the atrocities committed by him and others like him be permanently memorialized?

Joshua Mays: I see a monument as a marker in time and space, earmarking a particular page of the human story. A monument is a point of pause and reflection; to stop and ask how we emerged at this point and where shall we go next. Our monuments speak our values and our visions.

Emeka Ogboh: Working with Ursula Rucker, and the Chestnut Street Singers as the voices on "Logan Squared: Ode to Philly," with poetry inspired by Philadelphia and the feedback from the Monument Lab research in 2015, I've concluded that people are unique monuments, individually and collectively.

Karyn Olivier: A monument is ideally a catalyst that creates space for discourse. It should commemorate without stifling investigation and interrogation of our complicated histories from multiple perspectives. A monument should offer an opportunity to pose questions about our country's past and our histories' impact on the present without denying its complexity and messiness. It should allow each of us to see and imagine our critical role in the ever-evolving American story. A monument is an instrument — offering us a mirror to witness ourselves, our community, our city, our country — and imploring us to be active, engaged citizens in the world.

Kaitlin Pomerantz: Monument, from the Latin monere, to remind, advise or warn. Monument, a chance to put something on a pedestal, give it a name, mark its place. Monument, a lens into the past, a chance to change the future. Monuments, mighty or quiet, emblems of power or relics of power lost. Shelley described it right: "Two vast and trunkless legs of stone," a "shattered visage" amid the "lone and level sands," that decaying "colossal Wreck." Monuments, impermanent.

Ricardo Rivera: A monument is a reflection of our culture and society in how we honor and pay tribute to history. Instead of figureheads and false idols, we should memorialize ideas and experiences; a passage of time when society progressed. Beyond literal representations, monuments of the future will honor the moments and concepts that changed our society. Monuments can be abstract, immersive, and dynamic.

Alexander Rosenberg: A monument is paradoxical in its attempt to make permanent a fleeting moment or event. As I wander through Philadelphia, I am drawn to unintentional memorials – structures that were built and removed, others that were partially completed or temporary, projects that went unrealized. I find fragments of mistakes, replacements, and long-forgotten intentions. Both as an observer and a maker, I attempt to acknowledge the constant flux of the sites and subjects in question. What would it look like to see every version, past and future, of a given site? What is it to experience a site today, absent the effects of time?

Jamel Shabazz: A monument is a manifestation of an idea, conceived by the mind of an artist. The monument itself serves as a reminder, in many cases of a historic event or a significant person. Today in America, there are a lot of heated debates surrounding the relevance of certain monuments, mainly those that represent pride to some and oppression to others. The controversy is twofold and has served to divide the country once again. In order to move forward as a united nation, we are in need of monuments that reflect love and empathy in a world of much uncertainty.

Hank Willis Thomas: A monument is an idea or a mythology made "real" by manifestation in physical space that changes the meaning of that space, thereby making it charged, sacred, or holy. It is a marketing tool of a specific worldview that can only be challenged by destruction, removal, or the installation of something bigger and better in close proximity.

Shira Walinsky: A monument is a representation of core values and ideas of a society. We live in a turbulent time where monuments are sites of debate and struggle for our historical narratives. How can monuments allow us to see those who are unseen and underrepresented instead of only those who sit in seats of power and win wars? How can they allow for a reflection of imperfect or difficult histories? They should surprise visually and conceptually, make us question and inspire us to think about the kind of society we want to live in the future.

Marisa Williamson: A monument is a tool — a vessel into which communities can pour meaning, debate meaning, and redefine the terms of their coexistence. Like a wheel, a gear, or a lever, it can move previously immobile minds, and push minds further down the road toward progress. Monuments are ways of showing the past, not necessarily "the way it really was," but, as Walter Benjamin describes, "as it flashes up in a moment of danger." "In every era," he continues, "the attempt must be made anew to wrest the tradition away from a conformism that is about to overpower it."

Click here to read more about Monument Lab's public art project.