In AT&T Techs., Inc. v. Communications Workers of Am., 475 U.S. 643 (1986), the Supreme Court outlined the courts' role in determining arbitrability under a collective bargaining agreement: The courts . . . have no business weighing the merits of the grievance, considering whether there is equity in a particular claim, or determining whether there is particular language in the written instrument which will support the claim. The agreement is to submit all grievances to arbitration, not merely those which the court will deem meritorious. Id., 475 U.S. at 650. the Supreme Court reaffirmed the basic principles of arbitration. The first two principles guide our conclusion in this case. The first principle is that " 'arbitration is a matter of contract and a party cannot be required to submit to arbitration any dispute which he has not agreed so to submit.' " ( Id. at p. 648.) The second principle is that the question of arbitrability is for judicial determination "unless the parties clearly and unmistakably provide otherwise." ( Id. at p. 649.) The arbitration clause at issue in AT&T Technologies v. Communications Workers, supra, 475 U.S. 643 was part of a collective bargaining agreement. The court reasoned that the presumption of arbitrability furthers the national policy of peaceful resolution of labor disputes and achieves the parties' presumed objectives in collective bargaining. ( Id. at p. 650.) The court recognized, however, that parties would be less inclined to enter collective bargaining agreements if arbitrators were empowered to decide disputes the parties never agreed to submit to arbitration. ( Id. at p. 651.) Accordingly, regardless of policy considerations such as those at stake in collective bargaining agreements, the parties' agreement determines what disputes will be arbitrated.