Does rel= canonical combine link juice for 2 pages?

[SkinLaboratory]

If two pages are very similar, and one should rel= canonical to the other, will the page authority pass from the page with rel= canonical to the target page?

Also, what happens when you a page rel=canonical's to itself?

[TakeshiYoung]

If you're asking whether canonical tags pass PageRank, the answer is yes.

http://googlewebmastercentral.blogspot.com/2009/02/specify-your-canonical.html

[TomRayner]

The idea of the canonical tag is to help search engines identify the original URL and content and to ignore any versions of it.  If set up correctly, search engines will ignore and/or deindex the page with a canonical pointing to another page.

Therefore, on that premise, you are asking search engines to ignore the other page and all of its subsequent PageRank, authority, strength etc.

If you have a self referring canonical tag, this is telling Google to treat that URL as the originator and to ignore any other subsequent versions that are created either by yourself on another page, your CMS through a dynamic URL or query string or by people taking the content from your site and posting it elsewhere.  In essence, it should not effect PageRank or authority at all.

Hope this helps.