We can find numerous examples where individual pages ranked just fine without specific external links, as long as the website itself had external links pointing at it.
As long as your website itself is linked externally, it appears more than possible to rank individual pages on your site, even if those pages themselves don't have external links. That said, there's a strong relationship between links to a page, and that pages performance in search—so it's much better if the page actually does have external links.