Where can the quest of Qoheleth turn - when you follow the Great King what can you turn to? In Ecclesiastes 2-3 he first turns to consider wisdom and folly and madness.. He concludes that there is a qualitative superiority of light over darkness and wisdom over folly. Walking blind is not better than having sight.
Yet, he furiously concludes that a grievous thing happens! Whether wise or fool, death comes to all. Cancer doesn't check your worldview. The passing of time is ignorant of your good works. Death shows no partiality. It's cant and trite and weird to say otherwise.
This is hateful to Qoheleth. He hates life. Spirit-inspired Scripture says as much, and there is no reason to think that this is a quote of something false. Life lacks endurance and memory and legacy. Whatever you gain you not only leave behind but someone else picks up for free - and a fool could squander everything you achieved. Hate life. Hate work. Grievous wind-chasing. Rage at death. Mourn and grieve - cry "Abel".
Yet, we do have food and drink, life and work - and these are good gifts from God. They are a grace. The curse is intermingled with promises of lavish grace in Genesis 3-4 and so it is here (Ecclesiastes is arguably an exposition of Genesis 3-4 etc). Qoheleth says, let us enjoy God's gifts. Open your eyes in this hateful life to enjoy his grace. Knowing he graces those who are pleasing in his sight (those who trust him). Cry "Abel!".
A well known poetic interlude on time follows: consider time. Life has seasons, a time for this and a time for that. Just as space has been ordered by God who has time, this is cosmos not chaos.
[God] has put eternity into man's heart (3:11).
But this isn't as nice and fortune cookie as we tend to imagine. God does it so that we cannot discern the end from the beginning. If all we knew was our birth to our death we might get a grip on life - we might be free from the misery of vanity, unconcerned with legacy. Yet we know of more and can't grasp it. We desire but we cannot obtain. Ignorance might be bliss, but its not an option we have.
Consider God: where man is unenduring, God endures. Revealed and perceived - he is to be feared and trusted. Such is the way of belief in God. It's clear that this Qoheleth is no unbeliever. Consider his theology: This is a wise man. The man who hates life and his work sees also that food and drink and work are grace from God,. who senses that there is more than the hyphen between birth and death, who sees there is a God, who trusts him. The refrain sounds: enjoy life. Join the quest of one made wise for salvation by the word of God.
Consider justice. There is great injustice in the world - all can see. Even in this God has a design. He teaches us to long for the day he has appointed for judgement of the wicked and the righteous. There is death and there is resurrection. Though we're indoctrinated to not believe in death - we die. We're just dust and to it we return. Wake up! Learn that we're just like the beasts. Man is an image bearer of God but like the beasts, man die, we all die. Adam and Eve learned this as they were escorted from Eden, graciously clothed as beasts - a grace to teach of clothing in righteousness, a grace to teach of their beastliness: you shall surely die. A curse and a kindness.
The question is: 3v22: Who can bring man to see what will be after him?
a) We can’t do it ourselves. We want to but we can't. But, this doesn't result in nihilism or existentialism but to accepting our mortality and thinking of our legacy less while we enjoy the now gifts of God's grace.
b) God can. There are incomprehensibles and frustrations wired in by God. There is more beyond us and we're not the masters of our destiny. We can turn to and trust the Father, Son and Holy Spirit who are gracious - rage at the curse and rejoice in grace.
The wise still fly fairly blind, but they do so with joy knowing there is such a thing as sight.