Suppose I'm cloned when I am alive. Provided there is a technology that can copy ALL my mental states into the clone, such as memories, values, beliefs and the like. No more, no less. Also there is technology to produce the same body as me for the clone: same age and same structure. Now the clone stands in front of me. I will say 'I'm not the same person as this clone. we are two different persons.

Everyday I'm in the process of metabolism. My body(including my brain) is different from the one yesterday. My mental state can be said to be inherited from the one yesterday, But my metabolism doesn't make me a different person. I still think I'm Zhihao Wang regardless of whether this happens yesterday or today.

So what's the difference between metabolism and cloning in this case?

1 Answer 1


I am going to give an answer in broadly Aristotelian terms. The key difference is numerical identity -- which just means that you are separate from your clone. In other words, you and your clone are separate self-sustaining systems. Whatever else you have in common with your clone, each of you is a type of organism that engages in self-maintenance through ingestion, processing (metabolism), and expulsion of materials that keep you as roughly the same thing. Metabolism is merely the process by which the sort of organisms we are maintains itself.

You can say this in other Aristotelian and non-Aristotelian ways, you could say you and your clone have distinct souls (here meaning forms of a living thing are self-sustaining). You could say you and your clone have distinct haecity. You can say you are numerically different. You can say you are different time worms or that you can endure separately.

Basically metabolism is a process of a system. A clone is a distinct system that has its own processes.

  • Why don't say that the yesterday's me and the today's me are numerical different (i.e. they are two essentially, just the yesterday's disappear before the today's come into existence), but I treat them as one in some way? Commented Apr 18, 2014 at 3:55
  • You could take that view which would be called a "time-worm", but the reason you today and yesterday are not numerically different is that the you of yesterday maintained itself by taking in food and not falling apart until the you of today can appear. No known form of cloning works this way for humans.
    – virmaior
    Commented Apr 18, 2014 at 5:49
  • @wang: time is not 'real' the same 'you' are real. you don't exists as two entities 'yesterday you' and 'today you'. there is just you. and you exist. always 'now'
    – Cynapse
    Commented Apr 18, 2014 at 6:06

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