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This content is taken from the Humanists UK's online course, Introducing Humanism: Non-religious Approaches to Life, with Sandi Toksvig. Join the course to learn more.

Are there many truths?

It is worth addressing a humanist response to one other possible approach to the question of whether we can attain knowledge about the world. That is the response to relativism, the claim that there is no one single truth, but only different views, each true for those who hold them.

This is a view of the world that humanists will typically reject.

A difficulty with advocating relativism was apparent to the philosophers of ancient Greece. In one of Plato’s dialogues with Socrates, the sophist Protagoras claims that ‘Man is the measure of all things’, and that, consequently, all truth is relative. If that was the case, Socrates responded, then we are left with a difficult consequence: Does the claim that all truth is relative apply to itself? Is the claim ‘all beliefs about reality are equally true’ itself absolutely true, or is it only true for those people who believe it? If it is absolutely true, then we have a contradiction – not all truths are relative. If it isn’t, then relativism remains untrue for those of us who do not accept it.

This challenge does not prove that relativism is false, but it certainly undermines the relativist’s case that others – such as humanists – should accept it.

Humanists believe that we have a duty to use our intelligence as best we can to try to establish what is true. If relativism were true, there would be no point in thinking critically in this way, because whatever belief we ended up with after careful, rational reflection would be guaranteed to be no more true than the one we started with.

Simon Blackburn writes:

‘Protagoras said that man is the measure of all things. Well, suppose the issue is a nice one of measurement. What time is high tide at Newhaven tomorrow? I could have an opinion about that. But unless I have done my homework, it would not be likely to be reliable. Homework here means consulting tide-tables. Or, if it is my business to produce timetables it may mean something more direct, such doing some calculations, or perhaps going down to Newhaven with a measuring rod and a clock. It is true, of course, that a particularly awkward customer may dislike this measurement process, and it is open to him to argue for another. Like any human process, even simple measurement is fallible and may be conducted more or less well. But at the end of the day either the water stops rising at a given time, or it does not. Tide tables have their prestige not because of social and political machinations, but because they are reliable. Were there a competition, a marketplace for rival tables, success would eventually winnow out those that work from those that do not. Hence, Protagoras got only part of the way. Man indeed lies behind the measurement, but that does not mean we can conduct the measurement any which way. If we do, our ships go aground, and our projects are thwarted…

Voltaire Lecture 2001: Does Relativism Matter?

We will return to the challenge of ‘many truths’ when we explore moral relativism in Week 4, an area where the challenge carries potentially greater force and needs to be taken more seriously.

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This article is from the free online course:

Introducing Humanism: Non-religious Approaches to Life, with Sandi Toksvig

Humanists UK