In the original essay on the relational nature of personal identity, from October 10th, 2010, I wrote the following:

What are some of the typical components of personal identity?
1) Body
2) Consciousness associate with/centered in one body (including will and self-consciousness).
3) Memories of consciousness (as the direct causal product of 2)

But it seems to me that we should also include things such as:

4) Sets of beliefs
5) Attitudes/dispositions
6) Emotional make up
7) Ways of thinking about and approaching and evaluating the world (including others)

Now one might object that two individuals, X and Y, who are unknown to one another, who live on opposite ends of the earth might have exactly the same 4)-7), but we would not say that they are thereby, or to that extent, the same person; rather, they are just similar in those respects.

I am certainly sympathetic to that objection. However, here is where and how the threads of our identities begin to merge. When two people with different backgrounds and only some overlap regarding 4)-7) meet and then spend much time together, intimately engaging each other, and through that shared experience form common memories (so 3)) and in combination therewith exert causal/rational influence on each others’ 4)-7), creating a new kind of equilibrium in regard to them, then it is not that there is similarity of 4)-7) that constitutes shared identity. Rather, it is the mutual shaping of each other’s, and intermixing of, 4)-7) that allows for/constitutes this merging of certain threads/fibers of our being. It’s the causal/rational influence/connection between two people’s 4)-7), not just the similarity of their content that makes all the difference—the fact that two people’s shared 4)-7) is the product of mutual, reciprocal influence and not just coincidental similarity that constitutes the merged threads.

Now to some extent this phenomenon of shared identities occurs more broadly, especially and more and more with the use of technology to communicate and shape each others’ 4)-7). But it is strongest with those with whom we are closest:  family, friends, partners/lovers.

In a helpful response to this a friend of mine, Joshua Miller, pointed out that there’s a problem with the above account, namely, the idea that similarity is needed between X and Y if they are to, in some sense, share identities. Further, if we remove the requirement of similarity and stick with some notion of shared identity via reciprocal “impacts” on one another, then such shared identity would not be limited to our friends and loved ones; they would include those we don’t like. I think Joshua is right on both counts, though it doesn’t undermine the basic idea of the original post (and he didn’t intend his comments to do so).

So what is the idea exactly? Our interactions with one another include, for example, the things they say and do, and shared experiences. Regarding the idea that a person’s beliefs partially constitutes who they are, what another says can influence us to either share their beliefs or modify our beliefs in some way without sharing the same beliefs. How we react to the other has a similar effect for them—hence, the reciprocal nature of the identity formation.

But does this really result in having a part of oneself literally in common with the other? One might, after all, simply object that we’re confusing causal influence with the creation of a common element. Sure; who we are influences each other’s identities through our interactions, but such influence is not the creation of a common element. Moreover, what is this common element if we have done away with the previous idea of the similarity of beliefs, dispositions, etc.?

One response would be to note that the objection relies on the mistaken notion that our interactions create common elements. The shared identity that results from our interactions isn’t like the hip shared by conjoined twins. Rather, it is more like the way that Thich Nhat Hanh explains the Buddhist idea that he labels interbeing. In an article in the Shambhala Sun he is quoted as saying:

If we look deeply into a flower, what do we see? We also see sunshine, a cloud, the earth, minerals, the gardener, the complete cosmos. Why? Because the flower is composed of these non-flower elements: that’s what we find out. And, like this flower, our body too is made up of everything else….

As the sun is partially constitutive of the flower through its influence, so we are partially constitutive of each other. This is, again, not in the sense of the hip shared by conjoined twins. Instead, it’s in the sense that any definitive line between the sun and the flower will be arbitrary. We might think of this as a kind of vagueness of identity between sun and flower. This wouldn’t be linguistic vagueness, i.e., vagueness that results from some failure of our concepts. It would be vagueness in the world—something many philosophers don’t find acceptable.

The similarity of the sun and flower case is dissimilar to that between X and Y in at least one respect. The former is one way—flower to sun—whereas it is reciprocal or mutual with X and Y. Of course, the sun can exist without the flower. But not vice versa. And one might want to object: X can exist without Y and vice versa. The response is: yes, but X won’t be the same X, nor will Y, if they don’t interact.

The implications of this view are wide reaching. One of them is, as Joshua pointed out, that we also share identity with our enemies. This may be disturbing to some but it need not be for at least two reasons. First, it goes both ways. Insofar as our enemies are our enemies because of our differences, then through our interactions we form them, mitigating the amount of the “dark side” we perceive them as containing. Second, we are presumably much more profoundly shaped by, and thus much more profoundly a part of, our friends and loved ones with whom we spend the majority of our time.

Much more, as always, needs to be said. But this will due for now.