"When I was young and bold and strong, Oh, right was right, and wrong was wrong"
The words of poet Dorothy Parker who, in The Veteran, tries to tease out the age-old question: What makes people do the things they do?
Love, loneliness, lust, hunger, hurt, comfort?
A myriad of emotions drive every human behaviour that we find most difficult to understand.
The men who go out at night in search of sex for sale are no different. They're all propelled onto the streets by some innate desire.
But what happens to those who don't feel anything anymore? The women who find themselves numb?
It's midnight on Dublin's Baggot Street and a young woman steps out of the shadows. Low-cut top, tight jeans and rolls of jet black hair pulled tight, she carries with her a story. Like every girl who walk these streets.
Somewhere across town her young son sleeps soundly in his bed. In a sweet slumber that shields him from the darkness of his mother's whereabouts. He doesn't see the driver come to a stop as his eyes peel down his mother's legs.
She'll service three men tonight.
"I just want a bit of a feel and a blow?" the man says, approaching her on the corner. I look at her face and she nods as he goes to retrieve his car. Her polite smile hides her resignation. They'll make small talk on the way to her 'safe place' - the alley where she returns each night.
"How does it make you feel when you're doing it?" I ask.
She thinks for a while.
"I don't feel anything anymore."
Earlier this year she woke one morning and came down the stairs to find her long-term partner - the father of her child - dead on the couch.
She didn't cry at that moment either. Touching his pale-blue lips and cupping his grey face, she lay down beside him for hours before calling for an ambulance.
"I knew that once it arrived that would be it - I would never see him again. I needed to stay with him for a while longer."
She has been in the flesh trade since her teens.
I ask her about the theory that the women who fall into prostitution are often victims of sexual abuse as children.
The finding was put forward by Harold Greenwald, the late psychotherapist who carried out one of the most famous and extensive studies into the psychology of prostitutes.
"No. That never happened to me," she says nonchalantly. "When I was four years old my friend's older brother dry rode me, but he didn't do it naked. And I turned 14 when I first had sex, but that was with my boyfriend."
How old was he? I ask.
The requests vary.
"One man pays me to beat him with his umbrella for 15 minutes, while he begs me to stop. Some don't want sex - they just want me to talk. Others will beat you if they come too soon or try to rape you if they don't want to pay money up front."
The girls in the area agree a range of prices.
€30 for a handjob, €60 for oral sex and €80 to €100 for intercourse.
They vaguely know one another. But she speaks to them enough to keep one of their main rules: always use a condom.
She explains how some have HIV or hepatitis and clients regularly move between the girls.
So who is there to help?
"The guards are grand. They leave us be. They take our names and write down what we are wearing each night to keep an eye on us if anything happens."
But surely once you are attacked, a description of you will be too late?
She shrugs. "I know. They're just trying to help."
And Ruhama, the Dublin-based NGO which works with women affected by prostitution?
"They come around in vans and give us out soup and chocolate."
Meanwhile, two and a half years have passed since the government promised to review the laws on prostitution.
Now all we are told is that the Minister for Justice Frances Fitzgerald "may" propose laws targeting the buyers of sex.
While the inaction continues, Denise (not her real name) remains numb.
It's what she has always done to survive.
It has led her to become stuck in the world of prostitution with no feeling - no reason to motivate her - to get out of the trade.
"I need the money," she says. "I do it for my son."
"Inertia rides and riddles me:
The which is called philosophy."