Well, it would be a problem in two ways, the first of which is less problematic than the second: (i) taking intuition to be merely (even if irreducibly) epistemic & not semantic would mean that Russell couldn’t develop an adequate semantics for synthetic a priori propositions, which he actually remained committed to, even though he rejected idealism, & (ii) if the epistemic contribution of intuition to mathematical knowledge is irreducible, then Russell can’t reduce mathematics to logic alone, i.e., logicism fails. — Of course the failure of logicism is overdetermined by Russell’s paradox, Goedel’s incompleteness theorems, the Liar paradox, Frege’s “Caesar” problem about uniquely defining the numbers, etc., etc., so this would add only one more sufficient reason for its failure….