Royal Australasian Ornithologists Union early 20th century called themselves 'oologists', though the distinction between the notionally scientific discipline of oology and simple egg-collecting was blurred. Identification of any but the most common and distinctive species usually entailed the collection of specimens to be made into study skins. Modern field-guides did not exist and few people could afford the massive multi-volume, lavishly illustrated, handbooks of John Gould and Gregory Mathews. However, both Archibald J. Campbell and Alfred North had produced comprehensive guides to what was known about the nests and eggs of Australian birds, with illustrations of the eggs rather than of the birds themselves,
What Is History? art. Though Carr conceded that historians cannot predict exact events in the future, he argued that historical generalizations can supply information useful to understanding both the present and the future. Carr argued that since scientists are not purely neutral observers, but have a reciprocal relationship with the objects under their study just like historians, that this supported identifying history with the sciences rather than the arts. Likewise, Carr contended that history like science has no moral judgements, which in his opinion supports the identification of history as a science. Carr was well known for his assertions in "What Is History?"