"Nietzsche identifies five specific disadvantages of having too much historical knowledge. .. The five drawbacks are:
It creates too much of a contrast between what’s going on people’s minds and the way they live. E.g. philosophers who immerse themselves in Stoicism no longer live like Stoics; they just live like everyone else. The philosophy is purely theoretical. Not something to be lived.
It makes us think we are more just than previous ages. We tend to look back on previous periods as inferior to us in various ways, especially, perhaps, in the area of morality. Modern historians pride themselves on their objectivity. But the best kind of history isn’t the kind that is scrupulously objective in a dry scholarly sense. The best historians work like artists to bring a previous age to life.
It disrupts the instincts and hinders mature development. In supporting this idea, Nietzsche especially complains at the way modern scholars cram themselves too quickly with too much knowledge. The result is that they lose profundity. Extreme specialization, another feature of modern scholarship, leads them away from wisdom, which requires a broader view of things.
It makes us think of ourselves as inferior imitators of our predecessors
It leads to irony and to cynicism". https://www.thoughtco.com/nietzsches-the-use-and-abuse-of-history-2670323
The same moral impulse that found northerner sheltering runaway slaves during the American Civil War is now at work sheltering illegal aliens in the United States. The Fugitive Slave act was ignored then just as sanctuary cities ignore requests for cooperation from ICE today.
History teaches us that these feelings are present in everyone in every generation. This subject is examined in detailed in the Theory of Dual Morality.
I was reflecting on a passage of Plato's Republic which, in my opinion, has not gained the attention it would deserve; the passage, which is contained practically at the beginning of Republic book IX, tells:
"Well then, we were led much out of the way, while exposing this subject: what we want to recognize is this, that surely some terrible, savage, and lawless form of desires is in every man, even in some of us who seem to be entirely moderate; as it seems, this becomes manifest in the dreams. Consider, then, whether I seem to be saying something and whether you agree with me .”
“Well, I agree."
The passage is impressive, very impressive (at least I find it so). In spite of the fact that interpreters assign the described tendency of the soul exclusively to the tyrant, since Plato is describing the soul constitution of the tyrant, in this specific passage, apparently, Plato is speaking of men in general.
Applied to the discussion on history and on its being teacher of life, I think that I would agree with the definition, in the sense that history teaches us that and in which measure the tendency described by Plato has been - of course unfortunately - always very active in history itself.
In other words: something in men does not function (morally), and history can show it.
I know that this is a rather pessimistic observation on history, on its teaching and, generally, on men, but I think, nonetheless, that history, unfortunately, can teach very much on what men can be and of what men can be able to do.
Of course, men are not only these negative aspects, but they are these negative aspects too.
If we look around we can see the culmination of 7000 years of human social effort.
There is crime, yes, and rudeness, and hatred, but these are overwhelmingly overshadowed by homes, cars, the over-abundance of food, entertainment and laughter. We have made much of the world a veritable paradise for our species.
Look back 2500 years at the Greek or Persian conception of the Gods. They flew around in horse drawn chariots and tossed the occasional lightening bolt. That was about as good as the life of a God could be imagined. Now look at the lives of the people around us.
We all drive in cars and live in homes where we control the very temperature of our surroundings ... We watch TV and have a hundred well acted plays at our disposal at every minute. We fly in luxury over mountains and around the world. In our cars we carry around orchestras to listen to at our pleasure; and a computer that talks to us and can direct us anywhere we want to go.
Foods grown from all around the world are eaten at even the most humble tables. We have an understating of the origins of the universe, the composition of matter and energy, and the life cycle of stars. We have even seen men walk on the moon.
In other words, people today live better than even Gods could have been imagined to live throughout most of history.
And still we cry. But why?
The reason we have done so much is because we are never satisfied. No matter how well we live, we find problems to complain about and we seek to improve our current condition.
The most amazing and wonderful of all of man's capacities is his ability to be dissatisfied no matter how well he has it.
This pushes every generation to perpetually improve our conditions. We can hardly imagine how wonderful tomorrow may be!
No one is in a rush to get to Heaven because we may have it better here on earth.