If we fall into the common intellectual mode of despair it does not mean that the world has become any less joyous, it is we who have changed. Another philosophical structure that Virtue enlists is that it is likely that the ultimate truth is here among us, and in an explicit forum. If it is not, than this means that the Earth was set up in a way that doesn't care about our queries upon it. The question will arise. It becomes obvious that the way people thing things are, and how they perceive the world to be, is the way it really is for them alone.
Realism is at best subjective.
Schopenhauer said that the only logical world view is a pessimistic one, in life and after death. Anything he says can only pertain to himself, because another person's honest confession upon his deathbed of living and enjoyable life denies omnipresent, objective pessimism. Thus, a world view of optimism is equally valid. The world has a different shape for each face that looks into it. At least this is the way it is naturally, but due to entropy people would rather look at the world in a packaged way, in order to avoid a life or controversy and battle.