Are both "You can do no worse than" and "You can do worse than" accepted?

Question

I came across "You can do no worse than" in the following article:

You can do no worse than follow the regular updates that ESA astronaut Luca Parmitano is posting in his blog as he conducts his Volare mission on the ISS. He has provided fascinating, first-hand reports on life in space, handling fear, the mishap during his spacewalk and much else (Luca also has a Facebook page).

Logically, I would have expected You could do worse than [x].

Is "You can do no worse than" commonly accepted in everyday conversation, like I could care less which is bemoaned in Weird Al Yankovic's Word Crimes?

Answer 1

I believe that "do no worse" is a error in this case. I accept your logic. If I say "... do no worse than B" I mean there is nothing worse than B to be found anywhere.

Answer 2

Preamble

I see there is a long discussion about "I could care less". There's no need to read it because the expression can be justified simply as follows - simply take it to mean, "I could care less about X but not much less." Despite this, I personally use the standard version.

Before getting onto the precise case in point, let's look at its non-comparative version, "You can do no bad/ill."

"You can do no bad/ill [in my eyes]" means "You can only do good [in my eyes]" and is therefore a genuine litotes. It is a compliment and an expression of solidarity. Now we must look at how changing 'bad' to 'worse' (the comparative version) affects the issue.

Answer

Firstly I point out that the expression, "You can do no worse than...", already has a valid and commonly accepted meaning which conveys an aura of condemnation by pointing out the existence of a lower bound on evil.

E.g.

England - 1839 - ‎Read For all which complicated mass of evil, there remains, notwithstanding the senseless objections raised against it, (still it can do no worse, than leave things just where they are ;) there remains then no other remedy but “ the Ballot.” An Address to the People of England By England

https://goo.gl/Qid697

Now we come to the meat. Let's consider "You can do no worse ..." in the role of a litotes.

In strict logical terms, "You can do no worse [in my eyes]" means "You can only do better [in my eyes]" which is an expression of confidence in someone's future abilities. But is it appropriate in the case in point? The answer is a resounding 'No' for the following reason:

Let us unravel the litotes ...

You can do no worse than follow the regular updates

converts logically to

You can only do better than follow the regular updates

.. and that is clearly a condemnation of the updates.

Conclusion

1. The expression is common, but with a different meaning.

2. We understand the author's intention.

3. We can gloss over the error (or if we're reading fast, not even notice it).

4. Logically it does not pass muster.

It is therefore an understandable mistake but should have been picked up in the edit.