How to remove the comment_form's 'title_reply' field?

Hey, I figured out what I was doing wrong. Two things.

First, the title_reply field needs parentheses around the single quote marks.

'title_reply' => ( '' ),
instead of
'title_reply' => '',

Second, I placed title_reply in the wrong array. My code has two arrays, one nested within the other. The inner array with the comment_form_default_fields hook seems to be specific to the email, author and url fields. Whereas my first array, with no hook, seems to effect the rest of the comment_form defaults without a hiccup.

Here’s the working code.

<?php $comment_args = array( 'fields' => apply_filters( 'comment_form_default_fields', array(

	'email'  =>  more code...,
	'author' => more code...,
        'url'    => '' ) ), <!-- close apply_filters and second array -->

    'comment_field' => more code...,
    'comment_notes_after' => '',
    'title_reply' => ( '' ),

);
?>
<?php comment_form($comment_args); ?>

Please correct me if my explanation is wrong. Here’s a few tutorials and resources I found helpful.

http://ottopress.com/2010/wordpress-3-0-theme-tip-the-comment-form/
http://www.php.net/manual/en/language.types.array.php

http://devpress.com/blog/using-the-wordpress-comment-form/