Complex sentence: McCorquodale and Meehl (1948) discussed the distinction between what they called intervening variables and these hypothetica contrast, McCorquodale and Meehl (1948) describe hypothetical constructs as containing surplus meaning, as they imply more than just the operations by which they are measured.
Split into simpler sentences: McCorquodale and Meehl (1948) discussed the distinction between what they called intervening variables and these hypothetical constructs. In contrast, McCorquodale and Meehl (1948) describe hypothetical constructs as containing surplus meaning, as they imply more than just the operations by which they are measured.