title: Why does "The Little Schemer" insist that the second argument to `cons` must be a list?
body: <p>&quot;The Little Schemer&quot;:</p>
  <blockquote>
  <p>The Law of Cons <br />
  ... <br />
  The second argument to <code>cons</code> must be a list.</p>
  </blockquote>
  <p>Also, &quot;The Little Schemer&quot;:</p>
  <blockquote>
  <p>What is <code>(cons s l)</code> <br />
  where <code>s</code> is <code>'a</code> <br />
  and <code>l</code> is <code>'b</code></p>
  <p>No answer. <br />
  Why?</p>
  </blockquote>
  <p>But if I actually do <code>(cons 'a 'b)</code> I get <code>'(a . b)</code> which I know is not a list but it is valid - there is an answer - it is a pair...</p>