Let me begin the discussion. 

These quotes are from the Digital Companion to C.S. Peirce, an American philosopher and logician, who established pragmatism as a philosophy: 

http://www.commens.org/dictionary/term/assertion

1895 | Short Logic | EP 2:20

A proposition asserts something. That assertion is performed by the symbol which stands for the act of consciousness. That which accounts for assertion seeming so different from other sorts of signification is its volitional character.

Every assertion is an assertion that two different signs have the same object.

1895-6 [c.] | That Categorical and Hypothetical Propositions are one in essence, with some connected matters | CP 2.334-335

In every assertion we may distinguish a speaker and a listener. The latter, it is true, need have only a problematical existence, as when during a shipwreck an account of the accident is sealed in a bottle and thrown upon the water. The problematical “listener” may be within the same person as the “speaker”; as when we mentally register a judgment, to be remembered later. If there be any act of judgment independent of any registry, and if it have any logical significance (which is disputable), we may say that in that case the listener becomes identical with the speaker.

The assertion consists in the furnishing of evidence by the speaker to the listener that the speaker believes something, that is, finds a certain idea to be definitively compulsory on a certain occasion. There ought, therefore, to be three parts in every assertion, a sign of the occasion of the compulsion, a sign of the enforced idea, and a sign evidential of the compulsion affecting the speaker in so far as he identifies himself with the scientific intelligence.

1902 [c.] | Reason's Rules | MS [R] 599:5

An assertion is an act by which a person makes himself responsible for the truth of a proposition.

1902-03 [c.] | Reason's Rules | CP 5.543

Let us distinguish between the proposition and the assertion of that proposition. We will grant, if you please, that the proposition itself merely represents an image with a label or pointer attached to it. But to assert that proposition is to make oneself responsible for it, without any definite forfeit, it is true, but with a forfeit no smaller for being unnamed. Now an ex post facto law is forbidden by the Constitution of the United States of America, but an ex post facto contract is forbidden by the constitution of things. A man cannot promise what the past shall have been, if he tries. It is evident that to guarantee that, if a piece of work has not already been done right, one will pay for it, and to guarantee that, if it shall be found not to have already been done right, one will pay for it, have one and the same meaning. One or other of them therefore must be an elliptical or otherwise unliteral expression, or else both are so. But nobody will maintain that to promise to pay for the work, if it shall be ascertained not to have been already done right, really means to promise to so pay, if it shall in fact not have been already done right, whether it be ascertained or not. It would be equally absurd to say that there was any third meaning which should have reference to an unascertained past. It follows, then, that to contract to pay money if something in the past has been done or not done can only mean that the money shall be paid if it is ascertained that the event has happened or has not happened. But there would be no reason why the literal sense should not be understood if it made any sense. Hence there can be no meaning in making oneself responsible for a past event independent of its future ascertainment. But to assert a proposition is to make oneself responsible for its truth. Consequently, the only meaning which an assertion of a past fact can have is that, if in the future the truth be ascertained, so it shall be ascertained to be. There seems to be no rational escape from this.

1903 | Lectures on Logic, to be delivered at the Lowell Institute. Winter of 1903-1904. Lecture I | MS [R] 454:5

An act of assertion is a contract, the effect of which is that if what is asserted is not true, the assertor forfeits in a measure his reputation for veracity.

*

On the other hand, this should not be confounded with "argument by assertion." 

See: http://rationalwiki.org/wiki/Argument_by_assertion

Argument by assertion is the logical fallacy where someone tries to argue a point by merely asserting that it is true, regardless of contradiction. While this may seem stupid, it's actually an easy trap to fall into and is quite common.

This is not the same as establishing initial axioms on which to build a framework of logic or ideas.

*

Generalizations are part of the construction of an argument through reasoning. 

Both deductive and inductive reasoning involve broad generalizations. 

See: http://cherriporter.com/docs/introductiontorhetoricandargument.pdf

We can simplify a reply to the question now by saying that assertion creates a proposition (and risks the fallacy of argument by assertion and the assertor's reputation for truth), whereas a generalization is part of a reasoning process which attempts to demonstrate the truth of an assertion.

I hope this will initiate an interesting discussion.

Vincenzo Di Nicola

Psychiatrist and philosopher

University of Montreal

Comparing ‘assertion’ (A) and ‘generalization’ (G) -

Obviously these two concepts are entangled, but they can be distinguished from each other in specific contexts.

For the purpose of this answer, I would categorize both concepts into three broad contexts: intended A/G, alleged A/G, and hidden A/G.

For intended A/G, the writer/author makes the A/G intentionally or purposefully, and the A/G might be founded or unfounded. The slight difference is: The writer makes A based more on the certainty and/or importance of the judgment, and makes G based more on the volume of cases/contexts that the judgment applies to. ‘The author would assert that ....’ and ‘The author would generalize ...’ send different messages.

For alleged A/G, it is the reader that labels the judgment as A/G no matter whether the writer/author has such intention. Then the situation is a bit tricky: whether the statement is A or G to a certain extent depends on how the reader understands/interprets. By and large, a reader alleges an A based on his/her perception of the way the writer uses the words, but alleges an G based on his/her perception of the way the writer applies the logic.

For hidden A/G, neither the writer nor the reader is aware of the existence of the A/G, and whether it is A/G depends on how much new evidence will emerge in the future.

Generally speaking, A and G can be distinguished. On one hand, there are both asserted G and generalizing A. On the other hand, an A does not have to be a G, and vice versa. You can have both asserted G and tentative (not so firm) G. Also, you have A that involves generalizing a judgment/finding, and you also have A that is not generalizing anything. For example, the statement ‘[In my view] Trump is not going to be a popular president’ is an assertion which has nothing to do with any generalization. Similarly, ‘It seems that all people in the US are not impressed with the new president’s first day’ is generalization but not assertion.

Perhaps we can add a bit of linguistic analysis. It might help you show your students that indefinit pronouns, connectors and adverbs (i.e., some, a few, the majority, a little, great part, to some extent, generally speaking) tend to indicate a generalization.

On the other hand, the statements require that verb indicates no doubt, neither guesses nor possibility (for example, could, perhaps, should) that aren't present the types of words, which I mentioned earlier, and a connector style: without doubt, certainly, surely.

Finally, it is important to pay attention to the use of the verb "to be" in the academic text because you can specify both an assertion and a generalization.

Another distinction to be made is that generalizations are generally more vague in content - i.e. stress is bad for health - while assertions tend to be more concrete in their content - i.e. stress is bad because for health because it is associated with an overfluxuation of glucocorticoids. 

There will be fine lines ofcourse, a grey area in between both concepts as reiterated above.

Wouldn't it be simpler to just distinguish between the levels of both confidence and competence in those who tend to use assertions more than generalizations or vice versa?  When I listen to those who use both, I figure they know what they are talking bout aand thus less need for 'fact checking'.  All boils down to who you trust, right?

This is indeed a very rich discussion. While everyone approached the issue from a different perspective, there was a common understanding that ran throughout all postings. Vincenzo, I fully appreciate the dangers you allude to about argument by assertion. It is a trap that many students fall in to unconsciously. I must admit though that I have still not got my head around the difference between a proposition and the assertion of that proposition.

While my focus is skills development at an introductory level, the 3 broad contexts that Qilong brings to the discussion open up possibilities for more advanced study. 

Ben, I think you highlight an important overlap between assertions and generalizations. Finally, the linguistic markers that Marina highlights as well as the issue of content concreteness//vagueness (Mitja) add an important dimension to overall understanding.

Thanks for sharing.

Hi Olabisi,

Interesting question you posed and the discussion, as you note, is quite rich. I just found this thread, but I wanted to provide a quick response. As I have experienced, an assertion can be (and usually is) a precursor to a generalization. As many have stated, an assertion is localized to a specific argument (usually). The generalization is the attempt to broaden that assertion. That said, in the strictest sense, I suppose you could also ASSERT the GENERALIZATION. And maybe that's one of the reasons the original question sparked an interest!

Hope the conversation opened up some form of operational understanding for you. I found it interesting.

PG