 What is more, specialists also began to consider observations concerning the sight of newly born animals and babies when discussing Molyneux’s problem. Some of those doing research in the field, such as Adam Smith and Johannes Müller, supposed that the sight of young animals could be compared with that of a person who had been made to see. The fact that certain animals see objects at a distance as soon as they are born suggested that Molyneux’s question could be answered affirmatively. This turned out to be a strong argument against Berkeley’s theory of vision. Others, Thomas Brown for instance, were of the opinion that the visual behaviour of babies could be compared with that of a blind person who had been operated upon and made to see. They were convinced that in both cases seeing has to be learned, and that Molyneux’s question had, therefore, to be answered in the negative.