This paper presents new findings in Modern Irish which will provide insights into the current theory of syntax. There are three findings reported in this paper: (1) the subject/object asymmetry in wh-extraction; (2) the (non-)superiority effect; and (3) the syntactic property of the adjunct wh-phrase cén fáth 'why.' Based on these findings, we suggest (1) that the Minimal Link Condition from the viewpoint of the goal/attractee should be kept in grammar, (2) that it is necessary to define equidistance from the viewpoint of the probe/attractor, and (3) that cén fáth 'why' is only inserted at the SPEC of a [+Q] COMP, and never undergoes overt movement, so that LF lowering must be allowed in the theory of grammar.