The fate of humans and beasts
Whether the Preacher denies a difference between human and animal death, or speaks within the limits of what is seen.
Ecclesiastes 3:16-22
16Moreover I saw under the sun, in the place of justice, that wickedness was there; and in the place of righteousness, that wickedness was there.
17I said in my heart, “God will judge the righteous and the wicked; for there is a time there for every purpose and for every work.”
18I said in my heart, “As for the sons of men, God tests them, so that they may see that they themselves are like animals.
19For that which happens to the sons of men happens to animals. Even one thing happens to them. As the one dies, so the other dies. Yes, they have all one breath; and man has no advantage over the animals; for all is vanity.
20All go to one place. All are from the dust, and all turn to dust again.
21Who knows the spirit of man, whether it goes upward, and the spirit of the animal, whether it goes downward to the earth?”
22Therefore I saw that there is nothing better than that a man should rejoice in his works; for that is his portion: for who can bring him to see what will be after him?
What each tradition says
Rabbinic / Midrashic
Kohelet Rabbah 3:21 asks about the verse “And the spirit of the animal, does it go downward to the earth?” He answers that these are the souls of the wicked, who descend to Gehenna below.
Sefaria 2022 translation, Kohelet Rabbah 3:21 - The Sefaria Midrash Rabbah, 2022 translation — Kohelet Rabbah 3:21 (on Ecclesiastes 3:21)
Patristic
Gregory Thaumaturgus says it is uncertain whether the souls of men shall fly upwards. He likewise says it is uncertain whether the souls that unreasoning creatures possess shall fall downward.
Gregory Thaumaturgus (attributed), A Metaphrase of the Book of Ecclesiastes (trans. S. D. F. Salmond), in Ante-Nicene Fathers, vol. 6 — Chapter III, on Ecclesiastes 3:16-22
Catholic
Haydock, following Calmet, says few can prove that the human soul is immortal rather than that of beasts, since the bodies of both suffer the same inconveniences. He notes that this objection is answered in chapter 12:7.
George Leo Haydock, George Haydock's Catholic Bible Commentary (1859), on Ecclesiastes 3:21 (bibliaplus.org edition) — Comment on Ecclesiastes 3:21 (with Challoner and Calmet)
Orthodox
No sourced position found. Searched the CCEL ANF/NPNF texts already fetched (no Orthodox treatment of Ecclesiastes 3); pravoslavieto.com Philaret Longer Catechism Q. 115 calls the soul 'a substance spiritual and immortal' but has no comment on Eccl 3:16-22; archive.org PD English scans - none comment on the verse.
Reformed / Protestant
Matthew Henry holds that, as to spirits, there is a vast difference, but not a visible one. He says the spirit of the sons of men at death goes upward to the Father of spirits, to the world of spirits; it does not die with the body but is redeemed from the power of the grave.
Matthew Henry, Commentary on the Whole Bible, Volume III (Job to Song of Solomon) (CCEL) — Exposition of Ecclesiastes 3:21
Evangelical
Wesley says there truly is a difference, known by good men. But most people never mind it, since their hearts are wholly set on present and sensible things, and they take no thought for the future and invisible world.
John Wesley, Explanatory Notes upon the Old Testament - Notes on the Book of Ecclesiastes (Wesley Center Online text) — Note on Ecclesiastes 3:21