What are feelings for? Most nonscientists will find this a strange question. Feelings justify themselves. Emotions give meaning and depth to life. They need, serve no other purpose in order to exist. On the other hand, many evolutionary biologists, in contrast to animal behaviorists, acknowledge some emotions primarily for their survival function. For both animals and humans, fear motivates the avoidance of danger, love is necessary to care for young, and anger prepares one to hold ground. But the fact that a behavior. functions to serve survival need not mean that that is why it is done. Other scientists have attributed the same behavior. to conditioning, to learned responses. Certainly reflexes and fixed action patterns can occur without feeling or conscious thought. A gull chick pecks at a red spot above it. The parent has a red spot on its bill the chick pecks the parent's bill. The gull parent feeds its chick when pecked on the bill. The baby gets fed. The interaction need have no emotional content. At the same time, there is no reason why such actions cannot have emotional content. In mammals—including humans—that have given birth, mill is often released automatically when a new baby cries. This is not under voluntary control it is reflex. Yet this does not mean that feeding a new baby is exclusively reflex and expresses no feeling like love. Humans have feeling about their behavior. even if it is conditioned or reflexive. Yet since reflexes exist, and conditioned behavior. is widespread, measurable, and observable, most scientists try to explain animal behavior. using only these concepts. It is simpler. Preferring to explain behavior. in ways that fit science's methods most easily, scientists have refused-to consider any causes for animal behavior. other than reflexive and conditioned ones. Scientific orthodoxy (正统) holds that what cannot be readily measured or tested cannot exist, or is unworthy of serious attention. But emotional explanations for animal behavior. need not be impossibly complex or unstable. They are just more difficult for the scientific method to verify in the usual ways, cleverer and more sophisticated approaches are called for. Most branches of science are more willing to make successive approximations to what may prove ultimately unknowable, rather than ignoring it altogether. Many evolutionary biologists believe that