Cupitt believes that our ideas are products of language systems. The very categories of our thought, therefore, do not correspond to an objective truth or reality (hence the anti-realist tag).
This effectively places Cupitt’s philosophy within the broad category of nominalism: it means that he doesn’t recognise the real existence of universals. It means too that Cupitt won’t see words as pointing to some really existing entity that we might value for itself; there is nothing behind a word, except the meaning we, for the time being, have given to it.
It’s important to try to grasp all this, as there are important consequences to such anti-realism which you can’t help but recognise within liberal modernism.
For example, anyone holding to a Cupitt type nominalism is likely to favour a social constructionist view over an essentialist one. In other words, they are likely to believe that things which appear to be a natural part of reality are, in fact, mere inventions or constructs of a particular society at a particular time.
An example of this is the modernist attitude to gender difference. Liberal moderns often dismiss the idea that there are important natural differences between men and women as being essentialist. They prefer the idea that gender difference is an (oppressive) social construct.
Here is another example to consider. A writer criticising my views on nationalism recently wrote:
Mark Richardson wonders where liberalism stands on the nation state. The short answer, I think, is that classical liberals recognise the concept of “country” as an artificial construct that is not inherently something of value to be preserved ... To take the line that there is something inherently special about being Australian is to place undue emphasis on a word.
In this quote you get the idea of nominalism at work in the denial that the terms “country” and “Australian” point to any really existing entity. Instead, we are told that “country” is an artificial construct and that “Australian” is merely a word.
Conservatives need to know what we are up against. Some of our adversaries don’t even acknowledge, for philosophical reasons, the real existence of the entities we wish to conserve.