Comments on Putman’s Thought Experiment: Earth and Twin-Earth

The thought experiment with water and twater tries to convince that our beliefs and desires are not just a matter of what is going on in our minds, if I am interpreting it correct. When I change the example it seems to be more clear, for instance a case between Mary and Suzy. When Mary talks or thinks about her mother, or what the concept of mother means, she refers to someone that gave birth to her and is biologically similar to her. Suzy was adopted, (this is something Mary is not aware of) and she uses the word mother to refer to her adoptive mother. So when Mary talks to Suzy about her adoptive mother she is actually referring to her biological mother. Mary and Suzy both use the same word; mother, but the way in which they use it has different extensions. Maybe this is not a good example because the word mother has many different extensions when someone different uses it, but we can think of it in another way, where there is the existence of a twin earth. On twin earth twin- Mary is exactly the same as earthian- Mary along with everything else except the fact that mothers on twin earth are not biologically similar to their children. If Mary was unknowingly switched in her sleep with twin Mary, she would be using the word mother to refer to someone different then she believes. I’m not exactly sure of why these examples show that the contents of beliefs supervene on our internal states. This seems like it is not a stretch to think that your surroundings and what goes on inside you indicate what beliefs you hold. The examples show then that beliefs that seem to be the same belief- type are actually not because they have different content. So, coming from identical people the beliefs are not the same, so there has to be something other than internally that reacts on belief, but can’t we just say that the fact that we think the beliefs are not the same shows that you and twin-you are not exactly the same and therefore it should be expected that you and twin-you’s beliefs wouldn’t be exactly the same? What about two different people placed in the exact same situations and surrounding acting and doing the exact same things and having the exact same internal goings on but in two parallel worlds or universes, should each and every one of their thoughts be the same? This example seems to me to also show that beliefs are caused by internal and external components. The examples just seem to give you what would already seem intuitive.