Anaximander was the first philosopher (at least that I know of) to argue that the Earth floated in space without support and without being enveloped by the cosmic ocean. I have heard his reasoning for his belief stated differently in different places, either "because Earth is equidistant to all things", "because of it being the centre of the Universe", or "because its indifference to all things". I understand that his exact writings are lost and we will probably not know for certain exactly why he thought this implied the Earth did not need support, but what are some of the common interpretations of what he likely meant and where are these conclusions drawn from? Is his body of work widely represented in the literature?
Very few fragments extant.
The source is Aristotle, De Caelo, II, 13:
[295b10-296a21] there are some, Anaximander, for instance, among the ancients, who say that the earth keeps its place because of its indifference. Motion upward and downward and sideways were all, they thought, equally inappropriate to that which is set at the centre and indifferently related to every extreme point; and to move in contrary directions at the same time was impossible: so it must needs remain still. This view is ingenious but not true. The argument would prove that everything which is put at the centre must stay there.
See also: Carlo Rovelli, The First Scientist: Anaximander and His Legacy(2011),
and: Dirk Couprie & Radim Kočandrle, Apeiron: Anaximander on Generation and Destruction (Springer, 2017).