The physical body is the obvious identity, the one we are used to. But if we take quantum theory literally, as QBism does, and Everett, even your body is determinate only where observed, just like everything else. This is because your world hologram exists simultaneously in versions of the world in which, for instance, the specific arrangement of minor blood vessels inside your tissues is different; and your world, your physical reality, is the superimposed sum of all such worlds. The net result is that the arrangement is indeterminate.
Naturally, there is no ordinary physical reality in which this is the case. In physical reality, each version of your body is a real, ordinary, determinate body, with blood pumping through the network of blood vessels, all of which have real and specific arrangements. But your world is the superposition of all the worlds in which your world hologram exists. Effectively, as a result, even your body is indeterminate except where observed.
Stranger still, the same is true of the mind. The world of the individual defined by the world hologram is the sum of all worlds with this world hologram in the neural network. Thus it has the attributes and capabilities of all of them at once, which leads to fascinating implications as described in Quantum Computer. Creativity has a simple but bizarre origin.
The final point is the extraordinary significance of the self-concept in all this. Along with making observations of the rest of the world, one also makes observations of oneself. You see the outside of yourself in the mirror, and you are also constantly making observations of your internal state: body sensations and emotional feelings. And technically, every thought you experience is an observation of the state of the neural network of the brain. All this information is added to the record of observations, and forms part of the world hologram, a hugely significant part. This is the self-image. This is the self-concept avatar, meaning this is who you know yourself to be, here at the centre of your world.
This self-concept avatar is of course part of the world hologram. It is the integrated synthesis of all your observations of yourself, here at the centre of your reality. Strangely, it turns out that this alone defines the real you. Since only that much of the body that is observed is determinate, and the self-concept is the record of those observations, the self-concept is the definition of the determinacy of the physical body. In other words, the self-concept, that which one knows oneself to be, is all the definition one has as an individual in reality, on the inside view.
On the outside view, meaning in terms of objective physical reality, the self-concept is utterly irrelevant to the definition of anything physical. And on the outside view it is of course the DNA that defines all your physical characteristics. But in the personal world, your DNA, and all the things it defines about you, are indeterminate unless those things are observed. Only what is directly observed is determinate, therefore, in your world, your DNA is the superposition of all of the versions of DNA which could have given rise to your world hologram.
Just as the real world is indeterminate except where defined by the world hologram, the physical body is indeterminate except where defined by the self-concept. It is a strange thought but also quite amusing; you are exactly who you think you are. The self-concept is identically the same thing as the true identity in the physical world. At the same time, however, the identity is something much greater. The whole of the world hologram is what defines the individual: the rest of it apart from the self-concept avatar figure is the personal unconscious. And the strange attractors operating in the system bias the version of events at large in the world. One is not just the ordinary entity in the world, one is also the determinant of one’s reality. To borrow from Douglas Adams, you may find this disturbing; it scares the willies out of me.