In sociology, ontological security is a stable mental state derived from a sense of continuity in regard to the events in one's life. Anthony Giddens (1991) refers to ontological security as a sense of order and continuity in regard to an individual's experiences. He argues that this is reliant on people's ability to give meaning to their lives. Meaning is found in experiencing positive and stable emotions, and by avoiding chaos and anxiety. If an event occurs that is not consistent with the meaning of an individual's life, this will threaten that individual's ontological security. Ontological security also involves having a positive view of self, the world, and the future. The term "ontological security" was first introduced into the field of psychology in 1960 by R. D. Laing in his book The Divided Self. He used the term to distinguish mentally healthy individuals from those with schizophrenia and other schizophrenia spectrum disorders. According to Laing, a person with schizophrenia does not feel wholly embodied, but instead experiences a constant threat of implosion, coming from the outside world, which can eventually develop into hallucinations, delusions, and paranoia. This psychological sense of the term relates to basic symptoms of schizophrenia and self-disorders. The term was subsequently adopted by sociologists, but in a decontextualized sense – for example, sociologists would not claim that people who are not ontologically secure (in the sociological sense) have schizophrenia, or that home ownership, which is associated with ontological security, would prevent someone from developing schizophrenia. Philip A. Mellor and Chris Shelling talk about this concept in regard to thanatology, arguing that when death strikes, it causes people to "question the meaningfulness and reality of the social frameworks in which they participate, shattering their ontological security" Climate change poses a threat to people's sense of continuity in their lives.