input: Dali employed extensive symbolism in his work. For instance, the hallmark "melting watches" that first appear in The Persistence of Memory suggest Einstein's theory that time is relative and not fixed. The idea for clocks functioning symbolically in this way came to Dali when he was staring at a runny piece of Camembert cheese on a hot August day.  The elephant is also a recurring image in Dali's works. It appeared in his 1944 work Dream Caused by the Flight of a Bee Around a Pomegranate a Second Before Awakening. The elephants, inspired by Gian Lorenzo Bernini's sculpture base in Rome of an elephant carrying an ancient obelisk, are portrayed "with long, multijointed, almost invisible legs of desire" along with obelisks on their backs. Coupled with the image of their brittle legs, these encumbrances, noted for their phallic overtones, create a sense of phantom reality. "The elephant is a distortion in space", one analysis explains, "its spindly legs contrasting the idea of weightlessness with structure." "I am painting pictures which make me die for joy, I am creating with an absolute naturalness, without the slightest aesthetic concern, I am making things that inspire me with a profound emotion and I am trying to paint them honestly." --Salvador Dali, in Dawn Ades, Dali and Surrealism.  The egg is another common Daliesque image. He connects the egg to the prenatal and intrauterine, thus using it to symbolize hope and love; it appears in The Great Masturbator and The Metamorphosis of Narcissus. The Metamorphosis of Narcissus also symbolized death and petrification. There are also giant sculptures of eggs in various locations at Dali's house in Port Lligat as well as at the Dali Theatre and Museum in Figueres.  Various other animals appear throughout his work as well: ants point to death, decay, and immense sexual desire; the snail is connected to the human head (he saw a snail on a bicycle outside Freud's house when he first met Sigmund Freud); and locusts are a symbol of waste and fear.  Both Dali and his father enjoyed eating sea urchins, freshly caught in the sea near Cadaques. The radial symmetry of the sea urchin fascinated Dali, and he adapted its form to many art works. Other foods also appear throughout his work.

Answer this question "What type of symbolism did Dali use?"
output: The elephant is also a recurring image in Dali's works.

Question: Jonas Edward Salk (; October 28, 1914 - June 23, 1995) was an American medical researcher and virologist. He discovered and developed one of the first successful polio vaccines. Born in New York City, he attended New York University School of Medicine, later choosing to do medical research instead of becoming a practicing physician. In 1939, after earning his medical degree, Salk began an internship as a physician scientist at Mount Sinai Hospital.

In 1966, The New York Times referred to him as the "Father of Biophilosophy." According to Times journalist and author Howard Taubman, "he never forgets... there is a vast amount of darkness for man to penetrate. As a biologist, he believes that his science is on the frontier of tremendous new discoveries; and as a philosopher, he is convinced that humanists and artists have joined the scientists to achieve an understanding of man in all his physical, mental and spiritual complexity. Such interchanges might lead, he would hope, to a new and important school of thinkers he would designate as biophilosophers." Salk told his cousin, Joel Kassiday, at a meeting of the Congressional Clearinghouse on the Future on Capitol Hill in 1984 that he was optimistic that ways to prevent most human and animal diseases would eventually be developed. Salk said people must be prepared to take prudent risks, since "a risk-free society would become a dead-end society" without progress.  Salk describes his "biophilosophy" as the application of a "biological, evolutionary point of view to philosophical, cultural, social and psychological problems." He went into more detail in two of his books, Man's Unfolding, and The Survival of the Wisest. In an interview in 1980, he described his thoughts on the subject, including his feeling that a sharp rise and an expected leveling off in the human population would take place and eventually bring a change in human attitudes:  "I think of biological knowledge as providing useful analogies for understanding human nature.... People think of biology in terms of such practical matters as drugs, but its contribution to knowledge about living systems and ourselves will in the future be equally important.... In the past epoch, man was concerned with death, high mortality; his attitudes were antideath, antidisease", he says. "In the future, his attitudes will be expressed in terms of prolife and prohealth. The past was dominated by death control; in the future, birth control will be more important. These changes we're observing are part of a natural order and to be expected from our capacity to adapt. It's much more important to cooperate and collaborate. We are the co-authors with nature of our destiny."  His definition of a "biophilosopher" is "Someone who draws upon the scriptures of nature, recognizing that we are the product of the process of evolution, and understands that we have become the process itself, through the emergence and evolution of our consciousness, our awareness, our capacity to imagine and anticipate the future, and to choose from among alternatives."  Just prior to his death, Salk was working on a new book along the theme of biophilosophy, privately reported to be titled Millennium of the Mind.

Using a quote from the above article, answer the following question: Did he write any books on his biophilosophy?
HHHHHH
Answer:
" He went into more detail in two of his books, Man's Unfolding, and The Survival of the Wisest.