This, in contrast to your formulation, means that the effect of certain properties of Y is that X is impossible to achieve. I can see how it might appear that

This, in contrast to your formulation, means that the effect of certain properties of Y is that X is impossible to achieve. I can see how it might appear that way, but take note of the word "virtually" in the Webster's definition. It's an unfortunate word, because it undermines the absolute strength of the word it modifies...which, in your case, would be the word "impossible" (had you not dropped the word "virtually" from your paraphrasing, that is). Here's another example that shows someone else using the word in the same way that this author does. His system is copying files very slowly, and while technically his system is able to copy files, he feels it can't effectively be used for that purpose, even though a more patient person might disagree: http://www.vistax64.com/vista-performance-maintenance/120356-slow-file-transfer-effectively-cant-copy-move-files.html http://www.vistax64.com/vista-performance-maintenance/120356...