Are slippery-slope arguments ever valid?

Battle of Ideas festival 2023, Sunday 29 October, Church House, London


‘It’s a slippery slope’ is a phrase often used in politics. But the ‘thin end of a wedge’ argument can be complicated. If being flexible means always being open to abuse, how will we ever make any change? Why we can’t we simply decide to go a little way down the slope, rather than follow it to ruin?

On the one hand, it’s clear that some slippery slopes really are treacherous – many point to the government’s Online Safety Bill as an example of censorious legislation characterised as ‘safeguarding’ that opens the door to much broader restrictions of free speech. On the other hand, the slippery-slope argument can be used to counteract any suggestion of change, for fear of undesirable consequences. For example, some argue that the liberalisation of abortion law will lead to an increase in late-term abortions, or that the legalisation of assisted suicide will lead to a more callous approach to human life.

Slippery-slope arguments are nearly always conservative, in the sense of maintaining the status quo – and can often be used to simply shut down debate about moral issues that need serious consideration. If they rest on a hypothetical fear of change, should we resist their use? When policies and laws change, can’t we be trusted to know where the line should be drawn? Or, in a world where rules and boundaries seem terribly unfashionable, do we need such arguments to protect us from consequences we might come to regret?

Dr Piers Benn
philosopher, author and lecturer

Dr Heather Brunskell-Evans
philosopher; co-founder, Women’s Declaration International; author, Transgender Body Politics

Professor David Albert Jones
director, Anscombe Bioethics Centre; professor of bioethics, St Mary’s University, Twickenham; vice chair, Ministry of Defence Research Ethics Committee

Professor Kevin Yuill
emeritus professor of history, University of Sunderland; author, Assisted Suicide: the liberal, humanist case against legalization and Richard Nixon and the Rise of Affirmative Action

John O’Brien
head of communications, MCC Brussels