Call me a stickler, but I have noticed an increase in the use of the phrase "existential threat" being applied to all manner of things from Pacific Islands to the Great Barrier Reef. I am sure they mean that these things are in danger of ceasing to exist. The problem is that Jean-Paul Sartre coined the term "existential" as describing a philosophy that dealt with the "thrown" nature of human existence, i.e. the seemingly arbitrary nature of our being. The name was used to describe the philosophy of Soren Kierkegaard retrospectively and to a group of existential philosophers following Sartre. By "existential" they meant they dealt with the seeming lack of foundation of human existence. Thus, an existential threat is a threat to the spirit and therefore, to do with the theological sciences. This philosophy was taken up by various Christian theologians notably Paul Tillich who wrote a book called The Courage to Be.
Sartre is famous for his first novel Nausea Published in 1938 in which he traces the life of a Frenchman at the beginning of WWII who experiences a nausea of Being, a sliding, slipping and crumbling, not of the physical self, but of the soul. He is immersed in what Kierkegaard calls a "sickness unto death" the symptoms of which are known today as anxiety and depression caused by a loss of hope and, hence meaning.
The protagonist of Michael Houellebecq's new novel, Serotonin (2019) travels very similar terrain to that of Sartre's protagonist. Again, a Frenchman, Florent, well-educated and aware, finds himself in his late forties, orphaned, wifeless, childless and almost friendless. His parents had committed suicide at about his age because one of them was diagnosed with a terminal illness, and the other could not imagine life alone. He experiences panic attacks and depression for which his doctor prescribes an antidepressant that is designed to raise the serotonin levels in his brain.
He ruminates about two women with whom he had fallen in love. Neither relationships continued because career opportunities separated them. He muses that he would have asked either to be his wife but did not ask because it was considered abhorrent to stand in the way of a woman's career. His doctor, after seeing high levels of cortisol in his blood, pronounced that he was dying of sadness and that even if he raised the dose of his antidepressant, the side effects would make him obese and further damage his libido and deepen his impotence. The doctor gives him the names and numbers of some very skilled prostitutes who might help him out.
It is increasingly common to talk about brain chemistry as a way of explaining our mental and emotional life. The point of Houellebecq's novel is that conditions of existential crisis cannot be treated medically because they are a crisis of meaning. Scientism, the attempt to explain humanity in terms of physical cause and effect misses the human altogether. It has no language to describe the loss of hope that leads to despair and spiritual (then often physical) death.
There is a debate between social workers, psychologists, psychiatrists and neurochemists as to whether various mental illnesses are caused by brain chemistry, ie that they are endogenous. As far as I know, there exists no explanation of mental illness at the level of brain pathology, except for the various forms of dementia.
The other side of this debate, usually taken by non-medical practitioners, insists that damaging experiences, often sexual abuse, creates trauma to the brain that responds with abnormal chemistry. There are those who see attempts to change brain chemistry as treating the symptoms and not the cause and those who argue that treating the symptoms allows the sufferer to live a close to normal life. There is thus an ongoing debate about the role of neuro-pharmaceuticals in mental illness.
Houellebecq's novel presents us with a fictional account of someone who finds himself alone and despairing and who is driven to madness despite self-medicating with alcohol and nicotine and taking the latest prescription antidepressant. It seems that his predicament is not the result of particular trauma but of a bad orientation to his life, although having your parents abandoning you in a suicide pact must have its effect. It is a tenet of existentialist philosophy that mere existence is traumatic because it raises the unavoidable question about the meaning of life.
In the second last paragraph of the book Florent remarks:
"I could have made a woman happy. Well, two; I have said which ones. Everything was clear, extremely clear, from the beginning, but we didn't realise. Did we yield to the illusion of individual freedom, of an open life, of infinite possibilities? It's possible; those ideas were part of the spirit of the age; we didn't formalise them, we didn't have the taste to do that; we merely conformed and allowed ourselves to be destroyed by them; and then, for a very long time, to suffer the result."
If "Everything was clear, extremely clear" what impeded his action? Why did he not settle down with one of these women and raise a family? Surely this is what was "extremely clear". The consequences of not following that which was clear to Florent, twice, was that he was doomed to loneliness and despair, a despair that threatened to end his life prematurely. Something has happened in late modern culture that has thrown doubt on traditional ways of living. In this case, the desire for a career is more important than a long-term relationship. It is this disjunction that leads Florent to his present dilemma.
The second remarkable statement in the paragraph quoted above is: "Did we yield to the illusion of individual freedom, of an open life, of infinite possibilities? It's possible; those ideas were part of the spirit of the age;" The one belief that constitutes modernity is the idea of individual freedom. So much so that modernity has become the universal acid that dissolves traditional ties and isolates the individual. Behold, Enlightenment Man, sceptical of the old ways and affections, reliant on reason alone and vulnerable to the complications and turmoil that shear existence carries with it.