Our identities shape our place in the world. Inevitably, they play a large role in influencing the sort of point of view and experiences that one has. I suppose at it's most basic, the point is that identities/experiences are not discretely cumulative.
I'm a math person at heart so I can't help but think about in those terms. So what would it mean if identities were discretely cumulative? If we assume a norm of experiences as humans, you might think, each identity then adds a certain amount of experience. So let's say this baseline experience is b. Being white might add specific points of view/experiences, W; being black, B; and being gay, G. Thus being a gay, white male might give you the life experience of b+W+G and being a gay, black male might give you the experience of b+B+G. This would imply that the only difference, on average, between a gay, white male and a gay, black male, is their difference in race. Their experiences being gay would be identical.
It's a simple way to look at the world and initially maybe it makes sense. Don't all gay people, regardless of their other identities have something in common? Certainly. But it would be naïve to believe it was so concrete. If one believed that the world generally behaved as the paragraph above, it would mean that every time you interacted with another human being, you picked one characteristic of them and interacted solely with that part. It would mean that every time you saw an event or engaged in a conversation you only responded with one part of you.
For example, it would mean that if you were trying to catch up with a friend, you might be able to tell them about how it's going with your kids and how you feel about being a parent. At another point you might be able to tell them about how your relationship with your partner is going. However, you could never talk about how becoming a new parent has affected your relationship with your partner. Discussing how your parenting identity interplays with your partner identity would imply that identities weren't discrete. Allowing that interplay would mean that a single parent and a partnered parent might have different experiences as parents. We would no longer have a concrete set of experiences for parenting.
In reality, things are far more complicated and I think the above example illustrates that. Shared identities do often indicate a certain commonality, but it would be remiss to not recognize that a person's other identities' play a role in shaping how they see the world, how they interact with the world, and even how they relate to their own identities.
For example, I've often heard LGBT, white folks compare the LGBT civil rights movement to the Black civil rights movement. Far less often have I heard black, LGBT folks say so. Neither group is wrong. The LGBT rights movement is similar in the sense that its a marginalized community with fighting for equal legal rights. Both groups have had members of their own community lose their lives due to bigotry. There are no stakes higher than life itself. On the other hand, without diminishing the plight of LGBT folks, it's true that it's also not quite the same. LGBT people were not systematically enslaved and treated as property by straight people. I think that simple fact changes the nature of the struggle. The point is, identities cannot be separated.
But the consequences of this are not only personal. The consequences ripple far beyond our own individual experiences. I think some of the most articulate examples of this come from black, feminist writers. bell hooks writes in her essay, “The Integrity of Black Womanhood:”
“Assailed on the one hand by white patriarchy and on the other hand by sexist black men and racist white women, black women must be ever vigilant in our struggle to challenge and transform the devaluation of black womanhood. Those of us who advocate feminist politics must continually counter representations of our reality that depict us as race traitors. Throughout our history in the United States, patriarchal black nationalism has consistently represented any black female who dares to question sexism and misogyny as a betrayer of the race.”
Audre Lorde in her essay “Scratching the Surface: Notes on Some Barriers to Women and Loving” not only takes on the issues surrounding black feminism but also her identity as a black, lesbian feminist:
“At a recent Black literary conference, a heterosexual Black woman stated that to endorse lesbianism was to endorse that death of our race. This position reflects acute fright or a faulty reasoning, for once again it ascribes false power to difference. To the racist, Black people are so powerful that the presence of one can contaminate a whole lineage; to the heterosexist, lesbians are so powerful that the presence of one can contaminate a whole sex.”