When it comes to the world-famous Cirque du Soleil there are two camps - those who have seen it, and those whose best reference point is the scene in Knocked Up where Seth Rogan and Paul Rudd take mushrooms and go to see the show when in Vegas.
There is absolutely no disputing that there are moments of total and utter Fantasia - a shoal of pendulous paper lanterns adhered to the ceiling like the bodies of giant luminous seahorses; a performer pulsating her limbs in synergy with the music while balancing on one hand, as if a butterfly beating its wings; and a segment with trampolinists bouncing on to ledges on the wall, Super Mario Land-style.
All this without having eaten so much as a single shiitake. But hallucinogenic episodes aside, what Cirque du Soleil is about is so much more than just entertainment.
Divided into segments where circus artists put on a selection of differing performances, the onus of the show is that it is truly difficult to believe what your eyes are telling you is happening.
So, yes, absolutely the seahorses, the butterfly, the Super Mario Land, but also the vertical navigation of a ribbon up into the rafters of the Hydro, and the manipulation of two intertwining metal rings with a man inside until he is rolling around the stage so fast he becomes a lucky spinning penny.
Between each act, a band of mime-type characters play out a slapstick show to fill the gaps. I'm usually not a fan of time-killing - the TV adverts, the penultimate album track - but this feels OK because the senses need a break from the almost overwhelming optical illusions. And also because I try not to be too disparaging about segments, whatever their form: I suspect that they are usually simply a way of ensuring that there's something for everyone.
What is most incredible is that there appears to be no relationship between performer and floor - no thuds, or noises on impact, or really any clue to give away that the ground is there at all. The artists - and I'm struggling to know if that is the right term, but it feels right - move together in a sinuous eel-ripple.
Each segment transcends our expectations of how each act would usually be performed: during a skipping scene, one artist - who is jumping over various ropes already - produces a rope of his own and begins to skip inside the jumps. I'm not sure where he learnt that, but I think my gym should start putting meta-skipping on its itinerary. A tiny female acrobat lifts her male partner thirty feet for thirty seconds while entangled in a silk ribbon. It is a masterclass in knowing the strengths and loopholes of a body. It shows how it is possible to make it work harder, and work better.
There is no such thing as magic. This we know. But there is Cirque du Soleil, and I loved it. It is a show with extra oh! and I defy anyone in command of at least one of their senses not to agree.