We start off with quotes within the quote from M. Craig A. James who is quoting from the text Atheist Professor - Christian Student.
Student : Professor, is there such a thing as Heat?
Student : And is there such a thing as Cold?
Student : No, sir. There isn't.
(The Lecture Theatre became very quiet with this turn of events )
Student : Sir, you can have Lots of Heat, even More Heat, Superheat, Mega Heat, White Heat, a Little Heat or No Heat. But we don't have anything called Cold. We can hit 458 Degrees below Zero which is No Heat, but we can't go any further after that. There is no such thing as Cold. Cold is only a Word we use to describe the Absence of Heat. We cannot Measure Cold. Heat is Energy. Cold is Not the Opposite of Heat, sir, just the Absence of it.
This is so ridiculous it's embarassing. No professor of philosophy would be tricked by a stupid word game like this.
Student : What about Darkness, Professor? Is there such a thing as Darkness?
Professor: Yes. What is Night if there isn't Darkness?
Student : You're wrong again, sir.
Darkness is the Absence of Something. You can have Low Light, Normal Light, Bright Light, Flashing Light ... But if you have No Light constantly, you have nothing and its called Darkness, isn't it? In reality, Darkness isn't. If it is, were you would be able to make Darkness Darker, wouldn't you?
Again, this is the same silly word trick. The author is claiming there is no such thing as darkness. Darkness is merely a subjective, relative term that says, "Insufficient photons are stimulating the retina for this human's present needs."
Replace "darkness" with "emptiness" and see how it sounds. Suppose your coffee cup is empty. Would you say there's no such thing as emptiness because you can't make your coffee cup any emptier than it already is?
Ah, well, now it is time for me to do some response to Craig.
Atheist Professor having posed problem like "did God create Evil". Christian Student answers Evil is not a thing. He parallels with Darkness and Cold. They have no physical existence of their own but are defined as absense or too low presence of the Good Opposites.
Now, Craig A. James considers this a Magic Trick, since they still "exist" - but do they?
An empty mug exists. It may irritate owner by fact of being empty. But its emptiness does not exist. Its emptiness rather occurs. The mug is never really empty, when it is referred to as "empty" it means it is full of air even down to the bottom, usually. Its emptiness consists of absense of a good, specifically a drink (water, wine, tea or coffee ...) its owner would desire there. It is very true its emptiness can irritate. But for all that, it has no positive physical definition. It is not a thing created by God. Oh, God has created air that fills the cup as long as it is empty, but he has for all that not created emptiness as such.
But would not its eternal plenty be as bad or worse? Suppose it was eternally full of wine, God had created mugs that way, once you pour a liquid into them it stays full of that liquid forever.
You take a sip of wine. You put it back on table. Wine level rises to where before. You take another sip. And it is full of wine again. Might be pretty risky to some people? No?
And what if you wanted water? You could never empty the cup, even if you turned it upside down, since once you put it straight up again, the few drops left inside would quickly start filling the mug again. You would need another mug for water. And another one for milk. And another one for tea. And what if you wanted a drink you had given away the mug for? And what if you mixed two liquids that do not go together, like tea and coffee? You would be eternally stuck with the mixture (it is atrocious even to mix them in the stomach, I dare not imagine how it is to the taste!).
I think it is good for us mugs have been created such (in God's plan and man's work) that they can be empty - even if that means they will sometimes be empty when we do not want it.
It is also good for man not to have sympathy with each and every creature solliciting it every time. Otherwise one would so easily be overloaded. So it is good we have the freedom to cut off sympathy (and even an unsympathetic empathy*) when we need. It is not a freedom one should deprive each other of. Or ask God to deprive mankind of either. But this also means we have the freedom to not show sympathy when we actually should.
God has not created Evil, he has created Possibilities, and therefore also the Possibility of each Possibility working out for Evil on some occasion in some aspect. And the Possibility of Evil, unlike Evil, is Good.
Even Physical Evil (i e physical conditions of lower levels of things that comfort us, like life or like coffee, any level of seriousness) is sometimes a Good insofar as it is a Deserved Punishment.**
God sometimes causes Deserved Punishments (collectively or individually deserved, varies), but He never causes Moral Evil. Even if the Deserved Punishment is someone else's Moral Evil, God was not causing it, just using it to punish someone else's Moral Evil.
And Moral Evil is a lack of things in Angelic or Human lives that these angels or humans owe to God. Things that affect God as an empty or dirty or broken cup would affect us. If you want to know what "abhomination" means, imagine a cup that has been standing in the sink for one month (by my laziness I have seen such). Moral Good is what we owe God, either directed to Him or to Ourselves and Our Neighbour (Fellow Man, Fellow Christian) for God's sake.
This is a Christian theory of why there is Evil in a world that God created Very Good. It is very shortened, has not entered into the Historic and Theological Point of how Original Sin (the state we inherit from Adam's Sin) are a Culpability deserving of some Physical Evil, but it has I think made the point that Christian Student was not doing a shuffling of the logic, but rather Craig A. James a shuffling of terminology, confusing "exists and is created" with "occurs" as if everything that occurred would aslo be created rather than sometimes allowed by God, and also confusing "the fact there is evil is evil" with "the possibility of evil" being therefore also evil, as if possibility of one state were not also possibility of opposite and perhaps the only genuine possibility of opposite.
Meaning that Atheist Professor had no real point. And Craig A. James has not given him one. Meaning that Atheism is therefore not another name for thorough logic but for sloppy such.
St Thomas Aquinas has actually also dealt with why there is evil. First briefly in the Question-Article whether God actually exists, Summa Theologica Part I, Q 2, A 3:
Objection 1. It seems that God does not exist; because if one of two contraries be infinite, the other would be altogether destroyed. But the word "God" means that He is infinite goodness. If, therefore, God existed, there would be no evil discoverable; but there is evil in the world. Therefore God does not exist.
Reply to Objection 1. As Augustine says (Enchiridion xi): "Since God is the highest good, He would not allow any evil to exist in His works, unless His omnipotence and goodness were such as to bring good even out of evil." This is part of the infinite goodness of God, that He should allow evil to exist, and out of it produce good.
Note the wording "allow evil to exist" - not create it. Evil in angels come in Part I, QQ 63 and 64. Evil in Men is dealt with according to the understanding of the subject in Ist Part of IInd Part (I-II), QQ 71-89. By the way, the passage just quoted would be the case of Atheist Professor along with the response.
*Sympathy usually should either be empathetic or have the luck to coincide with what someone's own or someone wiser's sympathetic empathy would be. But empathy on the other hand can be there even if cut off from sympathy. Note that empathy can also be an illusion, one can think one understands someone without actually doing so.
**One can say that it is also part of the testing of those who are elect to glory, but even there there is an element of collective punishment for original sin.