<blockquote>
  <p>Objects are poor man's closures.</p>
</blockquote>

<p>Consider Java. Java is an object-oriented programming language with no language level support for real lexical closures. As a work-around Java programmers use anonymous inner classes that can close over the variables available in lexical scope (provided they're <code>final</code>). In this sense, objects are poor man's closures.</p>

<blockquote>
  <p>Closures are poor man's objects.</p>
</blockquote>

<p>Consider Haskell. Haskell is a functional language with no language level support for real objects. However they can be modeled using closures, as described in <a href="http://arxiv.org/abs/cs/0509027" rel="noreferrer">this</a> excellent paper by Oleg Kiselyov and Ralf Lammel. In this sense, closures are poor man's objects.</p>

<hr>

<p>If you come from an OO background, you'll probably find thinking in terms of objects more natural, and may therefore think of them as a more fundamental concept than closures. If you come from a FP background, you might find thinking in terms of closures more natural, and may therefore think of them as a more fundamental concept than objects. </p>

<p>Moral of the story is that <strong>closures and objects are ideas that are expressible in terms of each other, and none is more fundamental than the other</strong>. That's all there is to the statement under consideration.</p>

<p>In philosophy, this is referred to as <a href="http://en.wikipedia.org/wiki/Model-dependent_realism" rel="noreferrer">model dependent realism</a>.</p>
"Closures are poor man's objects and vice versa" - What does this mean?
<blockquote>
  <p>Closures are poor man's objects and vice versa.</p>
</blockquote>

<p>I have seen this statement <a href="http://c2.com/cgi/wiki?ClosuresAndObjectsAreEquivalent" rel="noreferrer">at</a> <a href="http://www.kimbly.com/blog/000063.html" rel="noreferrer">many</a> <a href="http://dotnetslackers.com/CSharp/re-198713_Epiphany_Closures_are_Objects_Objects_are_Closures.aspx" rel="noreferrer">places</a> on the web (<a href="https://stackoverflow.com/questions/501023/closures-and-objects">including SO</a>) but I don't quite understand what it means. Could someone please explain what it exactly means? </p>

<p>If possible, please include examples in your answer.</p>