On Slippery Slopes

My Times column tackles the misleading metaphor of the slippery
slope:

 

Who first thought up the metaphor of the slippery
slope? It’s a persistent meme, invoked in many a debate about
ethics, not least over the assisted dying bill for which I expect
to vote in the House of Lords on Friday. But in practice, ethical
slopes are not slippery; if anything they are sometimes too
sticky.

It is in genetics and reproduction that the slippery slope
argument gets used most relentlessly. The latest science to suffer
from the slippery-slope metaphor is mitochondrial replacement
therapy (MRT), a substantially British innovation, which promises
to cure human mitochondrial diseases by replacing the mother’s cell
batteries with those from a donor. It will be up to regulators to
decide if the technique is safe, but first it is up to parliament
to decide if it is ethically acceptable.

The only real objection to this intervention to allow certain
people to have their own children without horrible diseases is that
it is, in the words of one critic, “a slippery slope to
human germline modification”. Change the 0.002 per cent of genes
that are in the mitochondrion and what’s to stop somebody one day
changing the 99.998 per cent of genes in the nucleus of the
egg?

Here’s a perennial opponent of genetics, David
King, of Human Genetics Alert, on MRT: “Once we’ve crossed this
crucial ethical line, which says that we shouldn’t create babies
that have been genetically altered, it becomes very difficult to
then stop when the next step is wanted and then the next step after
that and we will eventually get to this future that everyone wants
to avoid of designer babies.”

But why would it be very difficult to stop? If MRT is legalised,
it would still be illegal to use it for any purpose other than
prevention of mitochondrial genetic disease.

A real slippery slope is a muddy hillside where one small,
apparently safe, step can lead to a slide to the bottom on your
backside. This is because, the physicists tell me, the static
co-efficient of friction is greater than the kinetic co-efficient
of friction, so it takes more force to start a bottom sliding than
to keep it going.

Look around current debates and it seems we stand atop veritable
mountain ranges of slippery slopes. Assisted dying will lead to
widespread euthanasia. Gay marriage will lead to approved
bestiality. Artificial life will lead to biological warfare. But
metaphors can mislead. There is no equivalent in the world of
politics to that change in the co-efficient of friction that
happens on muddy hillsides. It is easy to stop half way down a
moral slope; it’s hard not to. Each step meets fierce opposition
however well the previous step went.

When we do carry on down an ethical slope, progressively
changing the moral code, it’s not because it is slippery and we
wish we could stop, but because we have collectively decided we
want to go further at each stage. The Great Reform Bill was a step
on the road to universal adult suffrage, as many conservatives at
the time feared it would be, but it was hardly a slippery slope,
more of a lengthy struggle. The legalisation of homosexuality was
indeed a step on the road to gay marriage, as many religious people
feared at the time, but only because society chose to take each
subsequent step.

Over 40 years we have repeatedly been promised that bad things
will come of interfering in reproduction, but so far the good has
vastly outweighed the bad. The invention of in-vitro fertilisation
in the 1970s was much feared by many people as the precursor to
eugenics — people would use the technology to have superior babies
by using the sperm of celebrities. Wrong: the demand for
high-performance donor fathers is all but non-existent; the
technology is used almost entirely to help people have their own
babies, to cure the cruel disease of infertility.

Then in the 1980s research on embryos was going to lead
inexorably to the cheapening of life. It did the opposite, leading
to the development of techniques such as pre-implantation genetic
diagnosis (PGD), in which inherited diseases could be avoided,
reducing misery for thousands. But then PGD was going to lead to
eugenics for the rich, who would pick the best genes for their
babies. Not so. There is very little interest in using PGD to
“improve” normal genomes rather than avoid faulty ones.

In the 1990s, there was one technology that overreached. Gene
therapy — the attempt to replace a faulty gene in a particular
tissue using a virus to deliver a new version — did make an early
mistake, contributing to the deaths of some patients. But now the
technique is safely doing good on a growing scale.

Earlier this year, it was announced that six people with a
previously incurable form of blindness had improved their sight
after gene therapy. This follows successful gene-therapy trials on
children with various life-threatening inherited conditions.

After so many decades of seeing genetics and reproductive
technologies prove more beneficial and less open to abuse than
expected, you might think an intervention such as MRT had earned
the benefit of the doubt. Indeed, you might think that the
conservative side of this debate would have seen enough to change
its mind and recognise that the alleviation of suffering should
take priority over the pious recitation of moral platitudes and
appeals to faulty metaphors about muddy hillsides.

You might even, in a sense, think that the slope should be a bit
more slippery. If each step proves more beneficial and less harmful
to humanity than expected, then the next step should be taken
faster. But this is not the way such debates work. The track record
of previous innovations in medicine is ignored when we decide each
new possibility. The slope is sticky, not slippery.

It staggers me that the resistance to new techniques of genetic
and reproductive medicine comes mainly from the right, and the
religious right at that. Where, pray, in the Bible or Koran does it
say that it is better that a child — or an old person — should
suffer than that the sanctity of natural genomes and natural
ailments be interfered with? And all just in case some vague and
implausible crime be facilitated in the distant future. Slippery
slopes are red herrings.