The invention provides a method and apparatus for selecting desired attributes for system configuration. The invention uses one or more rule sets to define rules that are met when a configuration is valid. A rule set may specify the interrelation of attribute values within a product or between two or more products. If the combination of attribute values that specify a product conform to at least one rule in each of the rule sets that apply to that product, that combination of attribute values is considered to specify a valid product. If the combination of attribute values that specify all of the products of an assembly conform to at least one rule in each of the rule sets that apply to that assembly, that combination of attribute values is considered to specify a valid assembly.