“If you could just push a button, how many of you would like to live forever?” Dr. BJ Miller, a palliative care doctor and former executive director of San Francisco’s Zen Hospice Project, posed this question to a group of 25 hospice volunteers-in-training.

Only one person in the group raised her hand.

“Most of us don’t really hate death,” Miller said. “Life and death are deeply intertwined—it’s not as if we believe, ‘death, bad; life, good.’ For most people, the scariest thing about death isn’t being dead—it’s dying,suffering,”—a thought he’d also expressed in a TED Talk that has attracted millions of viewers.

Perhaps one of the reasons the idea of suffering is frightening is because it’s so complex. In 1982, Eric Cassell published an influential article in The New England Journal of Medicine, “The Nature of Suffering and the Goals of Medicine.” The article begins with an anecdote about a young sculptor who had metastatic breast cancer. She was receiving good medical care, Cassell emphasizes: The woman’s doctor was very kind, caring and competent. Still, every stage of treatment caused her severe suffering. The treatments disfigured her breast, made her obese, and led to the loss of her libido. She was confined to her bed at home and lost most of her hair. And she lost her strength in her left hand, the one she used for sculpting.

The sculptor had severe pain and physical symptoms, but her suffering was also affected by less tangible qualities, such as her relationships with others and her desire and need to work, Cassell writes. Her suffering was embedded in her culture—cultural definitions of what it means to be a woman, with breasts and hair and libido, for instance.

The sculptor’s experience was an example of how medical professionals were treating physical pain but failing to treat suffering, Cassell writes: “Pain is not suffering…and pain relief, although vitally important, is not the relief of suffering.”

But pain itself is also embedded in culture and identity and expectations. Pain is not the response of your nociceptors and their pathways to a noxious stimulus, according to the International Association for the Study of Pain. That’s because pain “is always a psychological state, even though we may well appreciate that pain most often has a proximate physical cause,” according to the organization’s website. While your nerves respond to sensations and communicate that message to your brain, your brain bases its response—its take on whether something is painful, and if so, how painful—on a number of factors, such as how long the sensation is expected to last, or whether you’ve caused it purposely by doing something like sprinting.

“When we talk about pain at the end of life, I think people mean all sorts of things: How much do they have, why do they have it, and how to respond, are all important but incredibly difficult things to get to,” says James Hallenbeck, a hospice doctor and palliative care expert. And it’s still only one part of suffering, which Cassell defines as the “severe distress associated with events that threaten the intactness of the person.”

By person, Cassell doesn’t simply mean mind, because the mind and body couldn’t really be divided into two separate entities. He gives several examples, including this description of the way we experience the past:

Memory exists in the nostrils and the hands, not only in the mind. A fragrance drifts by, and a memory is evoked. My feet have not forgotten how to roller-skate, and my hands remember skills that I was hardly aware I had learned. When these past experiences involve sickness and medical care, they can influence present illness and medical care. They stimulate fear, confidence, physical symptoms, and anguish.

Physical and mental experiences of suffering are inextricably intertwined. Persons, Cassell reminds readers, have roles as spouses, teachers, employees, parents, daughters or sons. They have regular behaviors, pasts, futures, and unconscious lives of which even they themselves are unaware.

And all of these affect how much suffering is caused by physical pain—and what will happen to us when we die.