Search engines see text; period. If you don't have any content on your site your chances of being found with a search engine query are pretty slim. In order to be considered for ranking it's IMPERATIVE to has some content on your Web site that search engines can grab a hold of and analyze for ranking. I ask my clients to put at least 250 words on each page in their site (this isn't a magic number, it just insures the page has a big chunk of copy). While some find it a quite daunting task, the one's that do add great content to their site see the pay off. Below are some links and resources to reinforce the idea of why this content is so necessary for your rankings.
Related Links and Resources
25 Ways to Add Quality Content to Your Web Site....
SEO Checklist - Look under #3 - Content
Search Engine Optimization
Search Engine Optimization: A Primer - look under "Content is King"
SEO Frequently Asked Questions (FAQ) - look under "Word Count"
Optimal Word Count & Web Page Copy Length
To Market to Market: Why Content is King