Here I am again, invading your space. The good thing about Op Ed pages is that you don't have to read them. So, if you will permit me to invade your space again, I want to send you another warning. If you don't want warnings, now would be a good place to stop reading.
My last warning (304) was about insisting that opinion writers validate their sources. I hope you didn't forget that because that article generated a response in which the author wrote: "...forget about certainty; there is no such thing in the real world." That comment was made close to the end of an article that was supposed to tell us to be careful about the kinds of logic we employ in our "real" world. Well, in my "real" world, it is a fundamental contradiction of logic to posit a certainty about the absence of certainty. It's like saying "there are no absolutes" when the statement is absolutist. This is what the philosophers call a self-destructive logical inconsistency. The plain facts are that certainties exist all over the real world and you will do yourself a great deal of good if you step around the reasoning of those who tell you that you can't know anything for certain. Their logic is fatally flawed and it leads to fatal ends.
Of course, that raises the question of the meaning of "certainties". What does it mean to be "certain"? There are two basic answers. The first is the philosophical answer in which certainty means that the thing considered "certain" is incapable of being contradicted or proven to be fallacious in the final analysis. This kind of certainty requires omniscience, or revelation from an omniscient source. Logical consistency would have to admit that there is no final certainty if there is neither omniscience nor access to true communication from an omniscient source. However, though we can deny that any creature has omniscience and remain rather "certain" about that (all of our experience reveals a certain level of foolishness even in the best of men and thinkers, which argues from empiricism that no mortal within the boundaries of our experience has ever demonstrated a possession of omniscience), it is not true that we can logically deny that an omniscient source has communicated certainties to at least some mortals. To deny that, we would have to have omniscience.
I hope you are tracking with me here. To be finally certain, one must at least be in contact with, or possess, omniscience. We can logically deny omniscience to anyone with a brain simply because a brain has a finite capacity for facts and that ipso facto denies the possibility of possessing omniscience. However, without omniscience, we cannot logically, or even empirically, deny the possibility of real and certain communication from an omniscient source. To do that would be logically inconsistent because such a denial would require us to have certain and comprehensive knowledge about every mortal who has ever lived and whether or not he/she received such communication. And, empirically, we cannot deny such communication for the same reason--we have not even come close to experiencing everything that is. That, philosophically, leaves the door open to the possibility of genuine certainties--if it can be established that omniscience has spoken.
The other answer is the "man on the street certainty". The man on the street is not typically interested in the machinations of the philosophers. All he wants to know is if he can be certain of anything at all. And my answer to him is "yes". He can know with certainty that he cannot get out of a room by simply walking into the wall. He can know if his wife and/or children are alive or dead. He can know whether he has a job or is homeless. He can be certain whether he is feeling healthy or sick. He can know whether his air conditioner is working or on the fritz. He can know a myriad of things that enable him to make decisions that will lead him in a helpful direction. And, believe it or not, he can know whether or not he has heard from an omniscient source. If he goes around denying his own proprietary interests and claiming there is no certainty in the real world, it is certain that he has not heard from the omniscient source. But his deafness does not mean that his experience is the norm that no one escapes.
So, my reader, keep insisting that opinion writers give you their sources, and keep your thinking cap on because there are still a lot of hucksters out there with something to sell you.