Let us imagine one world exceedingly beautiful....And then imagine the ugliest world you can possibly conceive. Imagine it simply one heap of filth, containing everything that is most disgusting to us, for whatever reason, and the whole, as far as may be, without one redeeming feature. The only thing we are not entitled to imagine is that any human being ever has or ever, by any possibility, can, live in either, can ever see and enjoy the beauty of the one or hate the foulness of the other.... [S]till, is it irrational to hold that it is better that the beautiful world should exist than the one which is ugly? Would it not be well, in any case, to do what we could to produce it rather than the other? Certainly I cannot help thinking that it would; and I hope that some may agree with me in this extreme instance. G.E. Moore, Principia Ethica
I sped past imaginings of this sort in an earlier post. Here, I want to pause and spend some more time with them. It will help us with an understanding what is true in our universe in which there is one person (Alph) and one desire (to gather stones).
These imaginings can serve a couple of purposes.
In one purpose, this serve as an argument against the idea that the only thing humans seek is the establishment of a particular brain state - be it happiness, satisfaction, or a surplus of pleasure over pain. It shows us that there are things that humans will choose - such as the realization of a beautiful planet rather than an ugly planet - even were the options do not include changes in brain states.
We see this interpretation particularly when we focus on the phrase, "Would it not be well to do what we could to produce it rather than the other?" Moore is asking about what we have reason to do.
In a previous post I gave Alph a desire that the planet Pandora B exists - a planet that may well fit Moore's description of an exceedingly beautiful world. This desire is fulfilled in any universe where the proposition "Pandora B exists" is true - even a universe where the propositions "Alph is experiencing Pandora B" can never be true.
In fact, we imagined a case in which Alph could bring the planet into existence only by destroying himself. Yet, given our initial assumptions, he had reason to bring the planet into existence, and no reason not to.
All of this matches one interpretation of Moore's famous example.
However, there is another interpretation of the argument. It may be interpreted to mean that the value of the beautiful planet exists within the planet itself. In a universe where no being capable of experiencing it even exists, it would still be better - in some impersonal observer sense - that the universe with the beautiful planet exist rather than the universe with the ugly planet.
Our model of Alph and his one desire does not support this.
One point to be made against the example interpreted this way is to ask, "Which is the beautiful world, and which is the ugly world?"
Moore asked us to imagine a world "of filth, containing everything that is most disgusting to us".
Note the phrase, "to us".
Let us imagine another creature - one that evolved from the dung beetle. Imagine the ugly planet being a huge ball of dung. To us, certainly, we may have reason to bring about the world that is beautiful to us and not the dung world. However, the dung beetle creatures have reason to bring about world that is beautiful to them - the big ball of dung - rather than the clean world of our imaginings.
This creates a problem for the idea that we can completely remove the idea of some type of creature with desires and interests in determining what is beautiful. If we cannot make a judgment of which planet is beautiful without having a subject and knowing something about them, we cannot make a judgment as to which world should exist even if could never be visited or seen.
Now, let us return Alph to his original state - the one where he has one desire, a desire to gather stones.
Now, ask him which planet should exist.
At best, he would answer with a shrug, though he has no reason to do even that much. Both options have the same relevance to making or keeping the proposition, "I am gathering stones" true. Because they have no relevance, they give Alph no reason for action - not even a reason to choose to answer the question.
To choose a planet to continue to exist is an action - but not one that he has any reason to take.