Frankenstein became a runaway best seller, and because no one could yet figure out how to make a movie of it, enterprising moguls settled on the next best thing, if not in fact a slightly better thing: the freak show. Here, in tents at traveling carnivals and on stationary boardwalks, were real monsters—giants, women with beards, skull-less embryos bobbing in jars—that were confrontable in carefully stage-managed environments. The rise of the zoo was an expression of the same phenomenon, as A. N. Wilson observes in his essential The Victorians. At a time when "disturbing thoughts were beginning to dawn in the public mind about the nature of humanity in the scheme of things," as he says, wild animals and mutants gave Victorians something to stare at in safety while asking themselves the big and suddenly urgent question: What, if anything, makes me different from that? In other words, what does it mean to be human?

Which is pretty much where we find ourselves again—hence my visit to the Mütter on this unbreathably hot morning. Thanks to the birth and rapid maturation of genetic engineering, artificial intelligence, and sophisticated pineapple-based facial scrubs that can give even a 50-something mother of 12 a sheen of nubility, at least in a darkened bar, humanity once again finds itself trying to solidify its own definitional boundaries. What are we? we're wondering again. How much could we change and still be ourselves? Where do we stop and the monsters begin?

And once again, like our angst-ridden Victorian forebears, we're using our eyes and our stomachs to do our thinking for us, to judge humanness.

Take the debate over embryonic stem cell research. The issue of whether frozen embryos who are doomed to destruction anyway are fair game for scientific experimentation has roiled the nation for the best part of a decade, yet has rarely progressed beyond a battle of competing visual aids. On the progressive, pro-research side of the argument—with which I happen to agree—a favorite tactic of those weighing in is to observe with postmodern panache that the frozen embryos in question are no bigger than the period at the end of this very sentence that I'm typing right now—as if anyone had argued that these embryos should be treasured for their sacred hugeness. President Bush, unconvinced, signed this year's veto of expanded stem cell funding in a room filled with adorable "snowflake babies," all of whom had at one stage been a frozen embryo in a lab and were now—indisputably—fully fledged booger-flicking American young people. As if anyone had argued that frozen embryos couldn't be grown into people given the right care and feeding and a few hundred grand's worth of special treatment by the very people whose funding he was now freezing.

Which is not to imply that anything particularly sinister or Orwellian, or even new, has happened to our powers of rational discourse. The blurring of ethics and aesthetics is a simple fact of human nature and one that's generally served us well. The near-universal opposition to torture, for instance (President Bush, once again, is unconvinced), arises not from the population having carefully waded through volumes of Hobbes and Foucault and arrived at a heavily footnoted opinion but from the fact that the sight of it, and the thought of the sight of it, simply makes us shudder. Because what if that were us? Over time we've managed to compile an impressive canon of moral principles by literally following our guts: that which makes us nauseated, or want to reel away in gibbering horror, must have something ethically wrong with it, and vice versa.

The trouble is—and this is new—that the next generation of freaks and monsters whose humanity we'll be charged with evaluating is likely to be rather easy on the eye. Positively gorgeous in some cases. As science continues to smooth out the rough spots and increase the functionality of the human blueprint, we may find ourselves not repulsed but seduced. It isn't rotten fruit and flaming torches we'll be hurling at the Elephant Men of the future but phone numbers and gift certificates. So smitten will we be with what our eyes are telling us, we'll be tempted to overlook the fact that Karen 3000 is one of a thousand monozygotic sisters or that an entire women's prison in Sweden had to die to make her piercing blue eyes.

And indeed it's with a certain wariness that I totter out of the Mütter Museum onto what Bruce Springsteen so aptly termed the streets of Philadelphia. The Victorian Age may have been a tough place to live in for those with a weak stomach or those, like me, with a finely tuned aesthetic apparatus, but at least the monsters of that time had the courtesy to declare themselves as such. As we enter an era in which wrongness and ugliness have dissolved their ancient alliance, I fear it won't be too long before—at the risk of sounding dramatic—they walk among us.

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