Let’s say the situation is this: you bought a physical copy of a textbook, and for whatever reason you want to view a pdf version of said book, maybe so that you don’t have to carry it around, etc., but strictly for personal use. From a cursory google search (and please correct me if I'm wrong here) it seems to be both legal and ethical to scan pictures of your own book and then use them strictly for personal use, not to be shared or distributed at all.
That being said, I'm curious about the ethical (and legal I suppose as well, but I assume this is illegal) concerns of reading a pdf scanned by another individual, or in other words, instead of scanning the book myself I use a pdf illegally distributed online.
Assuming all things are consistent between my book and the illegally distributed pdf (e.g. exact same edition of the book being scanned), is it unethical to use the illegal pdf?
My first thoughts are that it is functionally identical to what I would do if I was just slightly less lazy and did the scanning myself, and therefore ethical, but a counterargument that then comes to mind is whether or not giving the website the traffic that I do by accessing it taints the whole situation.