His influence was such that for example Alfred Marshall, founder of the Cambridge School of economics, would describe him as his "spiritual mother and father."
وكان تأثيره كبيرًا لدرجة أنه على سبيل المثال كان ألفريد مارشال مؤسس كلية كامبردج للاقتصاد يصفه بأنه (أمه وأبوه الروحيين).