5.A What a Line of Reasoning Is (REO-1.A, REO-1.B)

A paragraph can be stuffed with accurate sentences and still fail as an argument, because facts sitting next to each other aren't the same as facts supporting each other. An argument needs one claim to act as a reason for the next, so that accepting the first makes you more willing to accept the second, and so on until you reach a conclusion. That dependency is what a line of reasoning actually is: a sequence of claims, each one built on the claim before it, so the conclusion only stands if every link in the chain holds.

This chain can run in either legal order. You can lay out the reasoning first and save the thesis for the final sentence, letting the evidence build toward a landing point. Or you can state the thesis up front and then walk back through the reasoning that supports it. Both are legitimate structures, and writers choose between them based on whether they want to surprise the reader with a conclusion or orient the reader before showing the work. What's never legal is breaking the internal order of the steps themselves. If one step depends on information only a later step provides, the reasoning collapses, because the reader is asked to accept something before the ground for it exists.

This is why swapping two steps can wreck an argument even when every sentence stays true. The claims aren't interchangeable units — each one is a block holding up what comes after it. This sets up the next move in the unit: once you can see the chain, you can also see the block that's missing, the unstated assumption the writer needed to connect two steps but never said aloud.