I shall discuss many concepts, later in the book, of a similar nature to these. They are puzzling if you try to understand them concretely, but they lose their mystery when you relax, stop worrying about what they are, and use the abstract method.
Timothy Gowers in Mathematics: A Very Short Introduction, p. 34
It is important to keep in mind that this was written for laypeople, not for working mathematicians. What is “concrete” for a working mathematician can be very abstract for an average reader. For example, thinking of a 5-dimensional space is very concrete for a mathematician but very abstract to other people.
Timothy Gowers in Mathematics: A Very Short Introduction, p. 34
It is important to keep in mind that this was written for laypeople, not for working mathematicians. What is “concrete” for a working mathematician can be very abstract for an average reader. For example, thinking of a 5-dimensional space is very concrete for a mathematician but very abstract to other people.
That seems somewhat surprising coming from Gowers.