“Identity” here refers to the question “will my copy be me, and if yes, on which conditions?” It results in several paradoxes which I will not repeat here, hoping that they are known to the reader.
Identity is one of the most complex problems, like safe AI or aging. It only appears be simple. It is complex because it has to answer the question: “Who is who?” in the universe, that is to create a trajectory in the space of all possible minds, connecting identical or continuous observer-moments. But such a trajectory would be of the same complexity as all space of possible minds, and that is very complex.
There have been several attempts to dismiss the complexity of the identity problem, like open individualism (I am everybody) or zero-individualism (I exist only now). But they do not prevent the existence of “practical identity” which I use when planning my tomorrow or when I am afraid of future pain.
The identity problem is also very important. If we (or AI) arrive at an incorrect solution, we will end up being replaced by p-zombies or just copies-which-are-not-me during a “great uploading”. It will be a very subtle end of the world.
The identity problem is also equivalent to the immortality problem. if I am able to describe “what is me”, I would know what I need to save forever. This has practical importance now, as I am collecting data for my digital immortality (I even created a startup about it and the map will be my main contribution to it. If I solve the identity problem I will be able to sell the solution as a service http://motherboard.vice.com/read/this-transhumanist-records-everything-around-him-so-his-mind-will-live-forever)
So we need to know how much and what kind of information I should preserve in order to be resurrected by future AI. What information is enough to create a copy of me? And is information enough at all?
Moreover, the identity problem (IP) may be equivalent to the benevolent AI problem, because the first problem is, in a nutshell, “What is me” and the second is “What is good for me”. Regardless, the IP requires a solution of consciousness problem, and AI problem (that is solving the nature of intelligence) are somewhat similar topics.
I wrote 100+ pages trying to solve the IP, and became lost in the ocean of ideas. So I decided to use something like the AIXI method of problem solving: I will list all possible solutions, even the most crazy ones, and then assess them.
The following map is connected with several other maps: the map of p-zombies, the plan of future research into the identity problem, and the map of copies. http://lesswrong.com/lw/nsz/the_map_of_pzombies/
The map is based on idea that each definition of identity is also a definition of Self, and it is also strongly connected with one philosophical world view (for example, dualism). Each definition of identity answers a question “what is identical to what”. Each definition also provides its own answers to the copy problem as well as to its own definition of death - which is just the end of identity – and also presents its own idea of how to reach immortality.
So on the horizontal axis we have classes of solutions:
“Self" definition - corresponding identity definition - philosophical reality theory - criteria and question of identity - death and immortality definitions.
On the vertical axis are presented various theories of Self and identity from the most popular on the upper level to the less popular described below:
1) The group of theories which claim that a copy is not original, because some kind of non informational identity substrate exists. Different substrates: same atoms, qualia, soul or - most popular - continuity of consciousness. All of them require that the physicalism will be false. But some instruments for preserving identity could be built. For example we could preserve the same atoms or preserve the continuity of consciousness of some process like the fire of a candle. But no valid arguments exist for any of these theories. In Parfit’s terms it is a numerical identity (being the same person). It answers the question “What I will experience in the next moment of time"
2) The group of theories which claim that a copy is original, if it is informationally the same. This is the main question about the required amount of information for the identity. Some theories obviously require too much information, like the positions of all atoms in the body to be the same, and other theories obviously do not require enough information, like the DNA and the name.
3) The group of theories which see identity as a social phenomenon. My identity is defined by my location and by the ability of others to recognise me as me.
4) The group of theories which connect my identity with my ability to make plans for future actions. Identity is a meaningful is part of a decision theory.
5) Indirect definitions of self. This a group of theories which define something with which self is strongly connected, but which is not self. It is a biological brain, space-time continuity, atoms, cells or complexity. In this situation we say that we don’t know what constitutes identity but we could know with what it is directly connected and could preserve it.
6) Identity as a sum of all its attributes, including name, documents, and recognition by other people. It is close to Leibniz’s definition of identity. Basically, it is a duck test: if it looks like a duck, swims like a duck, and quacks like a duck, then it is probably a duck.
7) Human identity is something very different to identity of other things or possible minds, as humans have evolved to have an idea of identity, self-image, the ability to distinguish their own identity and the identity of others, and to predict its identity. So it is a complex adaptation which consists of many parts, and even if some parts are missed, they could be restored using other parts.
There also a problem of legal identity and responsibility.
8) Self-determination. “Self” controls identity, creating its own criteria of identity and declaring its nature. The main idea here is that the conscious mind can redefine its identity in the most useful way. It also includes the idea that self and identity evolve during differing stages of personal human evolution.
9) Identity is meaningless. The popularity of this subset of ideas is growing. Zero-identity and open identity both belong to this subset. The main contra-argument here is that if we cut the idea of identity, future planning will be impossible and we will have to return to some kind of identity through the back door. The idea of identity comes also with the idea of the values of individuality. If we are replaceable like ants in an anthill, there are no identity problems. There is also no problem with murder.
The following is a series of even less popular theories of identity, some of them I just constructed ad hoc.
10) Self is a subset of all thinking beings. We could see a space of all possible minds as divided into subsets, and call them separate personalities.
11) Non-binary definitions of identity.
The idea that me or not-me identity solutions are too simple and result in all logical problems. if we define identity continuously, as a digit of the interval (0,1), we will get rid of some paradoxes and thus be able to calculate the identity level of similarity or time until the given next stage could be used as such a measure. Even a complex digit can be used if we include informational and continuous identity (in a Parfit meaning).
12) Negative definitions of identity: we could try to say what is not me.
13) Identity as overlapping observer-moments.
14) Identity as a field of indexical uncertainty, that is a group of observers to which I belong, but can’t know which one I am.
15) Conservative approach to identity. As we don’t know what identity is we should try to save as much as possible, and risk our identity only if it is the only means of survival. That means no copy/paste transportation to Mars for pleasure, but yes if it is the only chance to survive (this is my own position).
16) Identity as individuality, i.e. uniqueness. If individuality doesn’t exist or doesn’t have any value, identity is not important.
17) Identity as a result of the ability to distinguish different people. Identity here is a property of perception.
18) Mathematical identity. Identity may be presented as a number sequence, where each number describes a full state of mind. Useful toy model.
19) Infinite identity. The main idea here is that any mind has the non-zero probability of becoming any other mind after a series of transformations. So only one identity exists in all the space of all possible minds, but the expected time for me to become a given person is dramatically different in the case of future me (1 day) and a random person (10 to the power of 100 years). This theory also needs a special version of quantum immortality which resets “memories” of a dying being to zero, resulting in something like reincarnation, or an infinitely repeating universe in the style of Nietzsche's eternal recurrence.
20) Identity in a multilevel simulation. As we probably live in a simulation, there is a chance that it is multiplayer game in which one gamer has several avatars and can constantly have experiences through all of them. It is like one eye through several people.
21) Splitting identity. This is an idea that future identity could split into several (or infinitely many) streams. If we live in a quantum multiverse we split every second without any (perceived) problems. We are also adapted to have several future copies if we think about “me-tomorrow” and “me-the-day-after-tomorrow”.
This list shows only groups of identity definitions, many more smaller ideas are included in the map.
The only rational choice I see is a conservative approach, acknowledging that we don’t know the nature of identity and trying to save as much as possible of each situation in order to preserve identity.