Is the outlook of Ecclesiastes pessimistic?

We will be reading selected passages from Ecclesiastes for three days. Like any book that you read more than once, Ecclesiastes gives you different impressions, depending on your station in life. Today, when I read chapter 1 again, I obtain an impression different from that I got three years ago. In the first go, the impression one gets from reading chapter 1 is that Solomon had aged and was exhausted in life.
I have seen everything that is done under the sun; and behold, all is vanity and a striving after wind.
What is crooked cannot be made straight, and what is lacking cannot be numbered (Ecclesiastes 1:14-15).
"all is vanity and a striving after wind" appears 9 times in the book and becomes the rally cry of Ecclesiastes.
Then, is Ecclesiastes a pessimistic book?
If we read only chapter 1, we cannot escape the conclusion above. Since wisdom literature is poetic, we have to read longer passages in order to get the feel. For example.
A generation goes, and a generation comes, but the earth remains for ever.
The sun rises and the sun goes down, and hastens to the place where it rises.
The wind blows to the south, and goes round to the north;
round and round goes the wind, and on its circuits the wind returns.
All streams run to the sea, but the sea is not full;
to the place where the streams flow, there they flow again.
All things are full of weariness; a man cannot utter it;
the eye is not satisfied with seeing, nor the ear filled with hearing (Ecclesiastes 1:4-8).
Now, do you feel the fatigue Solomon felt? Why was Solomon tired and exhausted? It was because however hardworking he applied himself, he was unable to satisfy himself, thus "the eye is not satisfied with seeing, nor the ear filled with hearing." Indeed, he was even tired of wisdom, tired of knowledge.
And I applied my mind to know wisdom and to know madness and folly. I perceived that this also is but a striving after wind.
For in much wisdom is much vexation, and he who increases knowledge increases sorrow (Ecclesiastes 1:17-18).
Why the vexation, why the sorrow? Is not wisdom something desirable? Francis Bacon once said, "Scientia potentia est (Knowledge is power)" Then, isn't knowledge also desirable?
The author of Ecclesiastes thought otherwise. It was because for him, all efforts had been futile. Yes, we increase our knowledge and accumulate our wisdom. Yet we cannot be satisfied. Then, why are we not satisfied? The answer has been given earlier.
There is no remembrance of former things,
nor will there be any remembrance of later things yet to happen among those who come after (Ecclesiastes 1:11).
We would not be satisfied because we know for sure that our efforts and achievements would not be remembered by future generations. This was the answer offered by the author of Ecclesiastes. But is it true?
This answer is probably true among arts and humanities, but not true among scientific disciplines. Isaac Newton once said, "If I have seen further it is by standing on ye shoulders of Giants." Along the line, we remember giants such as Copernicus, Galileo, Newton, Einstein, Bohr and Hawking etc. Of course, fallen along the roadside of scientific revolution, there are many unsung casualties whom nobody remembers. No wonder the author of Ecclesiastes sounded pessimistic.
Like it or not, Ecclesiastes is part of our culture, luring deep down our psyche. Here is the proof.
What has been is what will be, and what has been done is what will be done;
and there is nothing new under the sun (Ecclesiastes 1:9).
So, this is the origin of the idiom: there is nothing new under the sun.
Let me assure you, the more you read on, the more you will enjoy Ecclesiastes and perhaps agree with it.

My dear Advocate, who can fathom Your wisdom? Nobody can. So, let us open our arms and hearts to embrace Your wind. Amen.