Twenty Eleven does show the author in the ‘posted on ..’ line by default;
and it is in the html code of your front page; for example:
<span class="by-author"> <span class="sep"> by </span> <span class="author vcard"><a class="url fn n" href="https://www.existentialbuddhist.com/author/sethsegall/" title="View all posts by Seth Segall" rel="author">Seth Segall</a></span>
something in style.css must be hiding it;
this line:
.single-author .entry-meta .by-author {
display: none;
}
this is a (debatable) ‘feature’ of Twenty Eleven – not to show author info if the whole site is only posted by one author.
in your child theme’s style.css, add:
.single-author .entry-meta .by-author {
display: inline;
}
if you don’t have a child theme, edit style.css and either remove these lines or change from ‘none’ to ‘inline’;
however:
it is really recommended to use a child theme of the (default) theme Twenty Eleven;
a: to avoid that the modifications are overwritten with the next upgrade of your wordpress version;
b: to have a ‘fall-back’ theme if you have any major problems with themes in your installation.