Nice question. I guess it depends on how good the joke is. No, seriously, your question is a good riff on what seems to be the non-philosophers’ paradigm of a philosophical question, namely, ‘If a tree falls in the forest and there is nobody there to hear it, does it make a noise?’. I have to confess that when I first heard this I wasn’t at all sure what philosophical question it is asking, but I now take it that it is a question about the nature of sound. Is sound really just the experience of sound? Then if there is nobody around, there is no noise. But if sound is say really vibrations in the air, then the forest is noisy even when nobody is around. So what is nature of funniness? Maybe a joke is funny if it has the disposition to make people laugh. One consequence of this view is that jokes are funny even when they are not being told, because the disposition is there even when it is not being manifested. It’s just like pipe cleaners, which are flexible even when they are not being bent. So on this...

Even if beauty itself is is not in the eye of the beholder, the appearance of beauty is. But we don't always decide what we think. For example, you can't come to believe something just because I ask you to, even if you want to please me. Similarly, you can't decide what you will like and what you will hate. And the same goes for the appearance of beauty. If something appears ugly to you, you can't just decide to make it appear beautiful, even if you know you would be happier if you could. Some parts of our mental life are under our direct and conscious control; but lots of them are not.