In a world where Donald Trump declares an audio recording of his statements “fake news” and insists to supporters that “what you are seeing and what you are reading is not what’s happening,” it’s easy to despair for the truth. “We have entered an age of post-truth politics,” lamented the New York Times.

Simon Blackburn, philosophy professor at Cambridge University, isn’t worried. Blackburn, who received acclaim for his 2005 book Truth and has recently written another book on the subject, On Truth, says the truth has always been twisted by politicians. “In the nineteenth century the politician Joseph Chamberlain said of Prime Minister Benjamin Disraeli that he never felt the truth except by accident,” he wrote in his latest book.

The fact that so many people are upset at Trump’s lies shows that we still value and recognize the truth. “At the moment, enough people are aghast, and precisely because they expect people to be truthful about what they’ve said,” says Blackburn. In other words, the distress over “post-truth” discourse is in itself an indication that truth lives on.

In certain circles, though, lying goes unpunished. “Our attachment to truth has become liberalized, less moralized,” Blackburn notes. “It’s not quite such a serious misdemeanor if someone is caught out lying as it used to be.” Supporters of the likes of Trump in the US and Boris Johnson in the UK don’t condemn their favored politicians when they lie. But while liars are more easily forgiven than before, we still recognize their falsehoods; such leaders haven’t distorted the very nature of truth.

In Blackburn’s view, there’s no such thing as one definition of Truth, with a capital T. Instead, smaller truths hang together to create a coherent understanding of something. “In everyday life, we’re much more concerned with everyday truths: I know I have 10 toes, and so forth,” he says. “Many small truths build up my everyday sense of the world: who I am, what my history is, where I am.”

The fact that humans have 10 toes is a crucial example of Blackburn’s theory on truth, which is heavily influenced by pragmatist philosophers, such as 19th-century thinker Charles Sanders Peirce. Pragmatists believe that practical applications are the main indication of truth: If something works, then it’s true. Even those who are skeptical of the truth have a hard time denying that humans have 10 toes and two legs. After all, we act according to this fact every time we buy trousers with two legs.

But the focus on practical applications means that, when it comes to more complex issues, truth is not fixed. “In any interesting area, truth will always be provisional,” says Blackburn. “In an issue like Brexit, I suspect the truth will only be established if we wait and see,” he adds. In scientific inquiry, too, the truth shifts. In Pierce’s words, science “is not standing on the bedrock of fact. It is walking upon a bog, and can only say, this ground seems to hold for the present.”

This process of arriving at truth may be slow and fallible, but it slowly advances. More importantly, it’s the only means we have. When it comes to political disputes over facts, Blackburn says the only way to advance is by reasoning and seeking to persuade through nuanced dialog—a tall order in these increasingly polarized times. “The right method of fixing opinion is by inquiry, not by dogma or bluster,” he says. “You don’t get a truth in one big jump.”