I would like to do a non-color gradient, but am not sure how.

For example applying a blur filter in gradient. I.e., imagine the left side of the gradient fill area would be "normal", and as you go right, it would be more and more blury.

I'm exemplifying with "blur", but I'm trying to achieve this effect with other filter too. Is there any systematic way of doing this in an easy way?

I am using Inkscape.