Question

1. Since the beginning of time, some people have believed that the Earth is flat. Beginning around 300 B.C., however, some began to wonder if the Earth is actually spherical in shape.

Those that favored the flat Earth theory made the following observations:

The Earth is stable because it is a flat landmass sandwiched between a flat layer of air and a flat layer of water.


If the Earth is spherical, then oceans should be curved on top, but they aren't.


Some rivers flow for hundreds of miles but only fall a few feet. The rivers should fall farther if the Earth is spherical.

Answer 1

a it is not possible to settle a dispute.
b scientific knowledge is unattainable.
c argumentation is a necessary part of scientific inquiry.
d it is easy to resolve a scientific argument.

Answer 2

argumentation is a necessary part of scientific inquiry.

Answer 3

Those aren't very fair observations, meaning they're fairly silly or irrelevant, and don't adequately represent a good argument from a flat-earth theorist. A much better set of observations would center around the fact that everyday observation tells you everything is subject to a force pulling it straight down towards the surface of the Earth. Hence:

(1) If the Earth were curved, things would roll off the surface once it curved too far, in much the way things roll down hills once the slope gets too steep.

(2) If the Earth is not resting on something, it would fall, too. (We know the Earth itself is subject to the same forces, because if we dig a hole the earth we remove from it falls down just like any other object.) If the Earth is resting on something, it must clearly have a stable back, so it can't be spherical.

(3) We observe that over time hills are worn down flat by the action of rain and rivers. If the Earth were curved, rain and rivers would flatten it out.

(4) If the Earth were curved, surely the oceans would run downhill, drain off the edge, and be lost.

(5) Much of the Earth's surface is clearly ocean. Yet plain observation tells us the surface of water is always flat. How can the Earth be curved if it's mostly water, and water is always flat? (This is closely related to your third point, actually.)

The resolution of all these difficulties is the theory that gravity is a central force, meaning the net gravitational force of a collection of matter is essentially a force directed at the center of mass of the collection.