Full Idea
There are not enough constraints in the Formalist view of mathematics, so there is no way to select a direction for trying to develop mathematics. There is no part of mathematics that is more important than another.
Gist of Idea
Formalism is unconstrained, so cannot indicate importance, or directions for research
Source
Michèle Friend (Introducing the Philosophy of Mathematics [2007], 6.6)
Book Reference
Friend,Michèle: 'Introducing the Philosophy of Mathematics' [Acumen 2007], p.149
A Reaction
One might reply that an area of maths could be 'important' if lots of other areas depended on it, and big developments would ripple big changes through the interior of the subject. Formalism does, though, seem to reduce maths to a game.