Writing the Hypothesis
A hypothesis is a simple statement that gives the reader the writer's viewpoint. The writing of a hypothesis should begin after the writer is done Choosing a Topic. The most important characteristic of the hypothesis is that it provides an opinion. It is not a bland, factual statement. The hypothesis is a statement that should encourage the reader to think about what is written; to question it, to doubt it or even to agree with it.
Is that a hypothesis? No. The reader cannot question the validity, or truthfullness, of the statement. The war did indeed begin in 1861. That's fact.
Is that a hypothesis? Yes. Why? It's opinion. And because the reader could question the validity of the statement. That does not mean it's wrong. It just means that the reader could argue effectively that the statement is wrong, or the reader could agree with it. The writer would need to provide support to strengthen the opinion.