assertion versus statement

This may seem like a stupid question from an English teacher (2nd year), but I am confounded. What is the difference between writing an assertion to start a body paragraph versus writing a statement to begin a body paragraph? My sophomores are working on their research papers and a colleague of mine said he keeps getting statements versus assertion sentences at the beginning of his students' paragraphs. Is there truly a difference between the two? I thought as long as the "topic sentence" mentioned a part of the premise/assertion from the thesis statement, the body paragraph was set up to argue and support that particular line of argument. Am I just getting caught up in the minutiae or is there a literal difference. I want to be clear and concise so my students learn from this experience and I don't want to confuse them or teach them something that is incorrect. This is verbose, but I appreciate any and all advice.

Solution 1:

All assertions are statements, but not all statements are assertions:

• assertions are positive, but statements may be positive or negative;
• assertions do not supply proof or support, but statements may supply those.

Given that your colleague is suggesting a difference, it must be in those distinctions. Your colleague is seeing negative statements or statements that provide proof or support, or statements that are both negative and provide proof or support, rather than bald assertions, as topic sentences.

For a simple example, suppose the thesis is that fathers are more able to teach their children how to shoot guns. Then, the statement

Mothers may not have the experience they need to teach children how to shoot, because they have been deprived by their circumstances.

contrasts with the assertion

Mothers are less experienced shooters than fathers.

Whether this is what your colleague has in mind, I don't know (you'd have to ask, caprice being the norm). Likewise, whether or not requiring assertions as opposed to statements for topic sentences is pedagogically correct for your students is outside my purview.

Solution 2:

For what it's worth:

What your Colleague may have in Mind is that an Assertion is like a Hypothesis, while a Statement is a full-fledged Theory.

A Hypothesis does not require Proof: it is just an Idea. It may be Right, or it may be Wrong, and it's up to the Author to supply Evidence in Favor of his or her Hypothesis (assertion).

A Theory, on the other Hand, is Something that may already be Known to Others, along with all the necessary Evidence, just like a Statement.

Here's a statement:

John Singer Sargent was an American painter specializing in Realism and Impressionism.

Here's an assertion:

John Singer Sargent was an American painter who drew his inspiration from Rembrandt, Hals, Delacroix, Manet, and, to a lesser extent, William Meritt Chase.

There former is a well-known fact. The latter is an assertion: the author is expected to supply some evidence, verbal or otherwise, that would prove his point.