"So should you believe in parallel universes? The principal arguments against them are that they are wasteful and that they are weird. The first argument is that multiverse theories are vulnerable to Occam's razor because they postulate the existence of other worlds that we can never observe. Why should nature be so wasteful and indulge in such opulence as an infinity of different worlds? Yet this argument can be turned around to argue for a multiverse. What precisely would nature be wasting? Certainly not space, mass or atoms--the uncontroversial Level I multiverse already contains an infinite amount of all three, so who cares if nature wastes some more? The real issue here is the apparent reduction in simplicity. A skeptic worries about all the information necessary to specify all those unseen worlds.

But an entire ensemble is often much simpler than one of its members. This principle can be stated more formally using the notion of algorithmic information content. The algorithmic information content in a number is, roughly speaking, the length of the shortest computer program that will produce that number as output. For example, consider the set of all integers. Which is simpler, the whole set or just one number? Naively, you might think that a single number is simpler, but the entire set can be generated by quite a trivial computer program, whereas a single number can be hugely long. Therefore, the whole set is actually simpler. [...]

A common feature of all four multiverse levels is that the simplest and arguably most elegant theory involves parallel universes by default. To deny the existence of those universes, one needs to complicate the theory by adding experimentally unsupported processes and ad hoc postulates: finite space, wave function collapse and ontological asymmetry. Our judgment therefore comes down to which we find more wasteful and inelegant: many worlds or many words. Perhaps we will gradually get used to the weird ways of our cosmos and find its strangeness to be part of its charm.

If you liked Susannah's BoingBoing guestblog post of yore about The Operation (thanks, Kai), the experimental art-porn film shot with infrared, then you will dig this story about a French (of course) medical researcher using magnetic resonance imaging to observe how female internal anatomy accommodates a penis in a variety of sexual positions. I want pictures. The first BoingBoing reader to score them and post urls in this discuss forum -- or roll their own MRI erotica and post them online-- wins my undying blog-respect.

Update: Boingboing reader "ellison" shares these clinically accurate and decidedly non-prurient links to photographs from an earlier MRI-sex study referenced in the story above. Erotica, they ain't, but MRI images, they are. Link one, link two. > Update Two: aktiv1 shares a link to this very funny testimonial from a female Dutch anthropologist who discusses what it was like to be the subject of an earlier MRI-sex-photography project.