What does Carlo Rovelli mean by "blurring"? In Rovelli's book The Order of Time, he often refers to blurring.  Can you help me to understand what he means?  
He says we observe the universe from within it, interacting with a minuscule portion of the innumerable variables of the cosmos.  What we see is a blurred image. This blurring suggests that the dynamic of the universe with which we interact is governed by entropy, which measures the amount of blurring. 
What does this really mean?
 A: Blurring is Rovelli's "lay reader friendly" term for coarse graining. The following passage from his book makes this clear:

It follows that the notion of certain configurations being more
  particular than others (twenty-six red cards followed by twenty-six
  black, for example) makes sense only if I limit myself to noticing
  only certain aspects of the cards (in this case, the colors). If I
  distinguish between all the cards, the configurations are all
  equivalent: none of them is more or less particular than others.[18] The
  notion of “particularity” is born only at the moment we begin to see
  the universe in a blurred and approximate way.
Boltzmann has shown that entropy exists because we describe the world
  in a blurred fashion. He has demonstrated that entropy is precisely
  the quantity that counts how many are the different configurations
  that our blurred vision does not distinguish between.

In endnote 18, he says this:

The definition of entropy requires a coarse graining, that is to
  say, the distinction between microstates and macrostates. The entropy
  of a macrostate is determined by the number of corresponding
  microstates. In classic thermodynamics, the coarse graining is
  defined the moment it is decided to treat some variables of the system
  as “manipulable” or “measurable” from outside (the volume or pressure
  of a gas, for instance). A macrostate is determined by fixing these
  macroscopic variables.

Thus, saying "entropy exists because we describe the world in a blurred fashion" is Rovelli's "lay reader friendly" way of saying that "[t]he definition of entropy requires a coarse graining".
To read the gist of the argument that Rovelli makes in his book in the original scientific language, see Is Time’s Arrow Perspectival?, in which he uses the term coarse graining throughout.
A: He seems to me, reading this review: Rovelli: Physics and Philosophy  to be referring to three effects:
Blurring due to the  delay in the light from an object necessarily taking time to travel to our eyes, so there is "blurring" of  particular point in spacetime for all observers. So the notion of an exact "now" is gone.

The collapse of the notion of “the present” Rovelli considers to be “the most astounding conclusion arrived at in the whole of contemporary physics”.

Blurring due to GR related time delays near massive objects.
And finally:

Indeed, Rovelli points out that our entire conception of reality is blurred, necessarily – we can only discern the big events, not the infinitesimally small – and that this blurring effect offers a kind of mediation between the counter-intuitive quantum world and the Newtonian world in which we live.

The book, which I have started to read, is a translation, (so I would allow for that) and Rovelli is definitely, (imo), writing for a wider audience, and in a more literary style than you will normally find in popular science books.
With regard to entropy, I can only offer my own guess: he is trying to include the disorder inherent in thermodynamic processes to all aspects of the reality we experience. 
Yuk, that's a bit flowery, sorry, but I think that's what he's getting at.
Read the review linked above, see what you think.
A: To me blurring as Rovelli uses the term is a reference to the fact that we do not see order in certain states ....such as a shuffled card deck where the red and black cards might have been mixed together.  However that shuffled deck may have another specific order that would only matter if one were looking for it.   For example a lottery ticket that loses is no different than any other losing ticket (even if it's in sequence) so all those losing tickets get "blurred" together whereas the winning ticket is the only one that matters.  How we define disorder or entropy is a result of the "blurring" by which we view all states as equivalent if they are not the order we are looking for.  There is a mathematical way to express this....the chance that certain states would exist vs others without the input of heat or energy but it's over my head to get into that.   If I'm wrong about this than I understood that book even less than I thought I did!
A: I think the "blurring" idea (as a macrostate) may have implications for psychology and the study of attention and perception. At least, that is my question here. I understand that this is a physics-related question and there are "levels" issues in applying a core concept from physics (entropy) to human psychology. So my question is meant to open the conversation aside from this point. Rovelli's use of Horace's "Odes" throughout the book encouraged my interdisciplinary thinking here. I am not convinced that his use of the Ode is merely a literary device.
Basically, human attention (and its ontogenic and phylogentic evolution) is about the systematic reduction of blurring and the growing ability to apply any number of mental processes with greater degrees of freedom. More attention capacity = greater ability to reduce any distractions, to focus, and reduce the blur. If this parallel works, than the human perception of "time" at the macro-level is based on attentional capacity. The historical development of clocks -- and more recently, digitization of time -- plays a critical role in attentional capacity and direction: how culture/society manages, masters, and influences individual and societal use of time.
A lot of work has been done on the consciousness of temporality that could further help unpack the definition of blurring -- see https://stanford.library.sydney.edu.au/archives/fall2017/entries/consciousness-temporal/
