“All happy families resemble one another, each unhappy family is unhappy in its own way.” This famous remark by Tolstoy usually provokes a wry smile and a sage nod, but is it true and what exactly does it mean? We may paraphrase it thus: there is only one kind of family happiness, but there are many kinds of family unhappiness. Families are such that happiness in them comes in only one variety, but unhappiness in families has several varieties. This has the look of a proposition about families as such, but families themselves are various. Do we mean families with children, and how many children and of what sex, or are we including childless marriages? Must the parents be married? Must they be of different sexes? What of single parent families? Does happiness come in several forms if the family varies along these dimensions, or is Tolstoy’s statement to be limited to traditional families of a man, a woman, and three children of both sexes? Does the same point apply to couples before marriage: are all happy engagements alike while unhappy engaged couples come in different varieties? And what about romantic partners not contemplating marriage and family?
But why limit ourselves to family units at all—couldn’t we say the same about any social grouping? Are happy friendships all happy in the same way but unhappy ones variable in their mode of unhappiness? What about clubs or regiments or dinner parties or motorcycle gangs or rock bands? If these social units admit of the distinction Tolstoy identifies, it has nothing essentially to do with families, but applies equally to people forming groups of any kind. The trouble is that we are not told what it is about families in particular that generates the asymmetry in question, and it is not obvious what Tolstoy had in mind (or any of his sage assenters). Is it that happy families all have a strong but fair father, while unhappy families can have a flighty mother or a delinquent son or a disobedient daughter? That is hardly plausible: more plausible is the proposition that happy families contain happy members while unhappy ones contain at least one unhappy member—but then all unhappy families are unhappy in the same way. And what about the individual: can’t we equally say that all happy individuals are happy in the same way but unhappy individuals can be unhappy in different ways? Is it that my happiness resembles your happiness but that my unhappiness is unique to me? But surely I can be happy in virtue of something that doesn’t make you happy (e.g. being a kite surfer) and also unhappy about the same thing you are unhappy about (e.g. being short of funds). Whence the asymmetry? People vary, so what makes one person happy may not make another happy, and the same for unhappiness. Why should happiness be uniform but unhappiness multiform? And is it that Tolstoy’s statement is intended to apply only to family happiness—only it exemplifies the uniformity of happiness and variety of unhappiness? This takes us back to what is meant by “family” and whether the point generalizes to other social groups.
I can see one possible rationale for Tolstoy’s statement, but it doesn’t apply to families in particular or even to all social units; nor is it clearly true. This is that there are more things to be unhappy about than things to be happy about. As a rough generalization, people are happy when they are safe, well fed, and loved, though some may crave worldly success and plaudits; but they can be unhappy about virtually anything—their looks, weight, height, popularity, job, spouse, home, national politics, tennis game, literacy, numeracy, teeth, lack of riches, state of the world, death, the neighbors, etc. Happiness is found in a small number of things while unhappiness can be found all over the place. That seems right as a rough generalization about human nature: it explains why people who seem to have it pretty good can still find things to complain about. So happy people will converge in the things they are happy about, more or less, while unhappy people will tend to diverge in their cause of discontent. There are just so many things to be irritated about, disappointed in, furious over, and pissed with—while happiness seems to flow from just a few sources. Thus happy people will tend to be happy about the same things while unhappy people will vary in their list of peeves and grievances. This is the grain of truth in Tolstoy’s remark, but it has nothing particularly to do with families, happy or unhappy. Families will tend to he happy when their members are safe, well fed, and loved; unhappy families may be unhappy because of a domineering father or a feckless mother or a reckless son or a depressed daughter or a deceased pet or a paucity of bathrooms. There are not many things in this world to be thankful for, but of things to complain about there is no end. Consequently, one person’s happiness tends to resemble another person’s happiness while unhappiness can differ widely from person to person. Tolstoy doesn’t tell us the relative proportions of happy and unhappy families, but according to the explanation just given we might predict that unhappiness will preponderate, simply because there are so many causes of unhappiness to choose from. The same is true for human beings in general.
 But not for animals as far as I can see: they are not constantly seeking reasons to be miserable, or even naturally prone to bouts of depression; on the whole, they seem pretty happy, short of starvation and abuse. Tolstoy could not make his statement about, say, chimpanzee or elephant families.