Its interesting how we each develop in our own space. There's so much talk of how we share environments with each other. Generation X'ers have a different surrounding and hence different common personality trait from the new breed of young'uns, the Generations X+1'ers. One sort of division. Another is the gender selection based on genetic gender. And there are the blonde, brunette and redhead selection divisions. One could go on and on.
A few summers ago, I took this to its logical extension. In other words, I tried to define the individual as that person who has a unique overlap of all the appropriate groupings. I don't even need freewill to explain the existence of an individual this way. Let's say there are 1000 parameters, each of which varying exhaustively across all possible substitutable group memberships. For example, I might find one parameter to range across all economic classes possible. Another might range across all possible hair colours. So a person selects all of the parameters values in some fashion. Each selection places that person in a group with all other persons who made the same selection on that one parameter.
If a parameter(s) causes or determines another parameter, then the second is not an independent parameter, and is merely a sub-parameter. For example, if I choose to belong to the group(s) traditional married female then I automatically choose to have children. However, if the causally determining conditions are not selected, then what was a sub-parameter before, is not one here. To extend the example, if I choose to remain a single, unmarried female, I may or may not decide to have children. Etc.
This gets almost fractally complex. I want to lay out the picture even if it has many problems.
The standard thinking is that most people fall into a few parameter clumpings or package deals. This is independent of whether they are choosing the parameter settings with freewill or are absorbing them from the environment. This creates a four-way distinction of: the sheep who acquires an entire personality from the envirnonment; the person who does the same to appear to fit in perhaps; the sheep who fails to acquire a full personality from the environment; and the to some extent self-designed person.
If a person is a Republican in the US, then he or she also is from the religious right, white, employeed (or possibly female), etc. Further, he or she is against abortion, for capital punishment, against public health care, etc. The idea here is that republicans are not for abortion ... ever. Further, someone against abortion is also against public health care ... always.
In fact, the standard thinking is rather extensive. Most of us very casually stereotype others we know simply by picking out the most obvious details or parameters that the other displays, and imputing hte rest of a package deal to that person's personality. I have never done this, and it took me many years to believe anyone could ever think this way. But ... then again, I'm the one writing my most intimate thoughts on the Internet. :) And I do seem to have a preference amongst types.
Imagine that each parameter defines a Venn circle containing all people with that parameter. The individual is a person who is the only person in her Venn intersection. Many people will not have a unique intersection, but may have some very thin spots, making hteir personality type rarer. Others will clump as I suggested above. They will have many brethern who share the same set of Venn circles, including the overlaps. These are the easiest to stereotype upon meeting. If you've encountered one of their type before, then as quick as you can, recognize the package and generalize.
The issue was raised initially a few summers ago because I became annoyed at the increasing number of ever smaller special interest groups, each with an activist cell politically petitioning for funding from the collective whole - the government. With the continuance of the pattern, eventually, each of us will petition for our own purposes once again - if new clumps don't form as fast as others break up in differences. There could easily turn out to be an equilibirum ratio between individuals with unique issues, and groups of people with the same set of issues to deal with. I of course ignore that there are namy ways to specify humans individually - otherwise we wouldn't receive our own mail, phone calls, or email so easily.
So individuals are defined as a unique intersection of group memberships if the notion of group is atomic. And group is defined as containing all individuals with the relevant parameters incommon if thenotion of individual is atomic. It really doesn't make a difference logically.
These two perceptions make a difference when some of us use one system and some the other. Many people I know are anarchists or libertarians. They hold that each individual should live freely without governance from others who claim to know better. Society becomes an emergent property of the interactions between individuals. A group with one voice is perceived as a gang or a cult as much as anything else.
On the other, hand for those who claim that society comes before the individual, the person claiming to be an individual seems to be deluded, and in strong denial of their group status.
Who can win?!