For example, if you were performing educational research, you may assume that all students at the same school are from a very similar socio-economic background, with randomization smoothing out any variables.
By alerting the reader to the fact that these assumptions have been made, you are giving them the opportunity to interpret and assess the results themselves.
This means you're free to copy, share and adapt any parts (or all) of the text in the article, as long as you give appropriate credit and provide a link/reference to this page. You don't need our permission to copy the article; just include a link/reference back to this page.
You can use it freely (with some kind of link), and we're also okay with people reprinting in publications like books, blogs, newsletters, course-material, papers, wikipedia and presentations (with clear attribution).
You can also think of the Introduction as the section that points out the gap in knowledge that the rest of the paper will fill, or the section in which you define and claim your territory within the broad area of research.
The other job the Introduction should do is to give some background information and set the context.
If you want others to cite your paper, you should make sure they read it first.
Let us assume that the title and the abstract of your paper have convinced your peers that they should see your paper.
As long as you warn the reader about this, so that they are aware of the shortcomings, then they can easily judge the validity of the research for themselves.
This is much better than making them wait until you point the weaknesses out in the discussion.