In what is being billed as the world’s largest tax case, Apple Inc. appeared before the European Union’s General Court in Luxembourg on Tuesday to appeal a 2016 finding by the European Commission that the company owes €13 billion ($14.4 billion) in taxes.

During the first day of the two-day hearing, Apple lawyer Daniel Beard dismissed the Commission’s arguments that the company’s branches in Ireland should be liable for taxes on all sales outside the U.S., telling the court the claim “defies reality and common sense”, according to a report by Reuters.