Utopia is 'the forward dream' it expresses the possible. It is what is 'not yet' with the emphasis on 'yet'.
Utopia is essentially a society existing for the school on account of its being produced through scholarly reform.
Utopia is quite different from different groups. For orgiastic chiliasm (lower strata), liberal-humanitarian (intellectuals), conservative (status quo), and socialist-communist (proletarian).
Utopia is always made by a who has toothache, and therefore thinks happiness consists in not having toothache... that is, whose notion of the perfect society is merely a continuation of something that had only been valuable because it was temporary.
Utopia is valuable in that it wonderfully expands the imaginative horizons of human potentialities -but as guides to conduct it can prove literally fatal.