At Patheos, Justin Whitaker seems to be trying to reconcile Buddhist views on inherent nature with Kant, in particular with ideas about "good" and "evil." If that sort of thing interests you, you are welcome to read it, as well as Zen teacher James Ford's response to it. For now -- well, probably for later also -- I want to ignore Kant and just focus on the very beginning of the article --
"Is humankind naturally good or evil? One might quickly sidestep the question, saying that in Buddhism, humanity has no inherent nature, and so the question makes no sense."
I don't believe Buddhism teaches there is no such thing as human nature, which a dictionary defines as "the fundamental dispositions and traits of humans." As individuals we may be empty of an inherent self, but as a species we do seem to share some basic dispositions and traits. There is human nature as well as bird nature, fish nature, cat nature, and tree moss nature.
I found a dharma talk by Shunryu Suzuki Roshi that seems to address the question directly. Here are a few bits --
By nature human beings have good and bad sides, half and half. When you want to do something good, at the same time you don't want to do something good. [Laughing.] If you want to get up early, at the same time you say, "I will stay in bed five more minutes. It is too early!" At the same time you want to get up, you will say to yourself, "No, yes, no!" "Yes" is fifty percent; "no" is fifty percent ... or more! Bad things sixty percent; good, forty percent."...
.. Human nature is always the same. Some people may say our spiritual culture will progress when our material civilization progresses. Strictly speaking, however, as long as we have human nature, it is impossible to obtain a perfect idealistic spiritual culture in our human world. We should fully realized this point. Because of our uneasiness, we are too anxious to achieve something perfect in our spiritual life. ...
... Some people may say, if human nature is always the same, then it is useless [laughing] to practice zazen, to study Buddhism. But our study is based on this fact. Our study is not to improve upon the actual fact that we have good and bad, half and half, as our human nature. We should not try to improve upon this actual fact. Even Buddha accepted this truth ... he started Buddhism based on this fact. He accepted this truth. If you try to change this truth, you are no longer a Buddhist.
The Roshi is pointing to the Four Noble Truths here and saying that being born human is to be born into ignorance and craving, which leads to dukkha. And let's not forget the Six Realms -- to be born into the human realm is to be marked by curiosity as well as craving. Is that not human nature?
As to whether humans are "naturally" good or evil, I think it's important to keep in mind that "good" and "evil" as they appear in the sutras are not necessarily the same concepts as "good" and "evil" that pop up in western philosophy. The words from the Pali Tipitika that are most often translated "good" and "evil" are kusala and akusala, which (I'm told) literally mean "skillful" and"unskillful." In other words, they are not something you are, but what you do.
James Ford mentions the Two Truths --
We often speak of two truths, that phenomenal world where we are born and die, where we love and hate, where every thought and every action has a consequence, and the open, boundless, empty realm, where all categories collapse more completely than if captured by a black hole.
The "good news" of the Zen path, at least as I've encountered it, is that we can and do know both these realms as our intimate truths.
So in the phenomenal world birds fly, fish swim, cats nap, and people strive to make sense of things, because it's their nature. The teachings on emptiness do not deny that.