The man of system, on the contrary, is apt to be very wise in his own conceit

From Theory of Moral Sentiments by Adam Smith.

The man whose public spirit is prompted altogether by humanity and benevolence, will respect the established powers and privileges even of individuals, and still more those of the great orders and societies, into which the state is divided. Though he should consider some of them as in some measure abusive, he will content himself with moderating, what he often cannot annihilate without great violence. When he cannot conquer the rooted prejudices of the people by reason and persuasion, he will not attempt to subdue them by force; but will religiously observe what, by Cicero, is justly called the divine maxim of Plato, never to use violence to his country no more than to his parents. He will accommodate, as well as he can, his public arrangements to the confirmed habits and prejudices of the people; and will remedy as well as he can, the inconveniencies which may flow from the want of those regulations which the people are averse to submit to. When he cannot establish the right, he will not disdain to ameliorate the wrong; but like Solon, when he cannot establish the best system of laws, he will endeavour to establish the best that the people can bear.

The man of system, on the contrary, is apt to be very wise in his own conceit; and is often so enamoured with the supposed beauty of his own ideal plan of government, that he cannot suffer the smallest deviation from any part of it. He goes on to establish it completely and in all its parts, without any regard either to the great interests, or to the strong prejudices which may oppose it. He seems to imagine that he can arrange the different members of a great society with as much ease as the hand arranges the different pieces upon a chess-board. He does not consider that the pieces upon the chess-board have no other principle of motion besides that which the hand impresses upon them; but that, in the great chess-board of human society, every single piece has a principle of motion of its own, altogether different from that which the legislature might chuse to impress upon it. If those two principles coincide and act in the same direction, the game of human society will go on easily and harmoniously, and is very likely to be happy and successful. If they are opposite or different, the game will go on miserably, and the society must be at all times in the highest degree of disorder.

A classic articulation of the age-old struggle between the Humanist vision and the Totalitarian vision. Thomas Sowell refers to this as the Constrained versus Unconstrained Vision (in A Conflict of Visions by Thomas Sowell.) It has also been described as the Tragic Vision of man versus the Utopian Vision. Steven Pinker describes these different views in The Blank Slate.

In the Tragic Vision, humans are inherently limited in knowledge, wisdom, and virtue, and all social arrangements must acknowledge those limits. "Mortal things suit mortals best," wrote Pindar; "from the crooked timber of humanity no truly straight thing can be made," wrote Kant. The Tragic Vision is associated with Hobbes, Burke, Smith, Alexander Hamilton, James Madison, the jurist Oliver Wendell Holmes Jr., the economists Friedrich Hayek and Milton Friedman, the philosophers Isaiah Berlin and Karl Popper, and the legal scholar Richard Posner.

In the Utopian Vision, psychological limitations are artifacts that come from our social arrangements, and we should not allow them to restrict our gaze from what is possible in a better world. Its creed might be "Some people see things as they are and ask 'why?'; I dream things that never were and ask, 'why not?'" The quote is often attributed to the icon of 1960s liberalism, Robert F. Kennedy, but it was originally penned by the Fabian socialist George Bernard Shaw (who also wrote, "There is nothing that can be changed more completely than human nature when the job is taken in hand early enough"). The Utopian Vision is also associated with Rousseau, Godwin, Condorcet, Thomas Paine, the jurist Earl Warren, the economist John Kenneth Galbraith, and to a lesser extent the political philosopher Ronald Dworkin.

In the Tragic Vision, our moral sentiments, no matter how beneficent, overlie a deeper bedrock of selfishness. That selfishness is not the cruelty or aggression of the psychopath, but a concern for our well-being that is so much a part of our makeup that we seldom reflect on it and would waste our time lamenting it or trying to erase it.

[snip]

In the Tragic Vision, moreover, human nature has not changed. Traditions such as religion, the family, social customs, sexual mores, and political institutions are a distillation of time-tested techniques that let us work around the shortcomings of human nature. They are as applicable to humans today as they were when they developed, even if no one today can explain their rationale. However imperfect society may be, we should measure it against the cruelty and deprivation of the actual past, not the harmony and affluence of an imagined future. We are fortunate enough to live in a society that more or less works, and our first priority should be not to screw it up, because human nature always leaves us teetering on the brink of barbarism. And since no one is smart enough to predict the behavior of a single human being, let alone millions of them interacting in a society, we should distrust any formula for changing society from the top down, because it is likely to have unintended consequences that are worse than the problems it was designed to fix. The best we can hope for are incremental changes that are continuously adjusted according to feedback about the sum of their good and bad consequences. It also follows that we should not aim to solve social problems like crime or poverty, because in a world of competing individuals one person's gain may be another person's loss. The best we can do is trade off one cost against another.

[snip]

In the Utopian Vision, human nature changes with social circumstances, so traditional institutions have no inherent value.
That was then, this is now. Traditions are the dead hand of the past, the attempt to rule from the grave. They must be stated explicitly so their rationale can be scrutinized and their moral status evaluated. And by that test, many traditions fail: the confinement of women to the home, the stigma against homosexuality and premarital sex, the superstitions of religion, the injustice of apartheid and segregation, the dangers of patriotism as exemplified in the mindless slogan "My country, right or wrong." Practices such as absolute monarchy, slavery, war, and patriarchy once seemed inevitable but have disappeared or faded from many pads of the world through changes in institutions that were once thought to be rooted in human nature. Moreover, the existence of suffering and injustice presents us with an undeniable moral imperative. We don't know what we can achieve until we try, and the alternative, resigning ourselves to these evils as the way of the world, is unconscionable.

I would add that the Achille's Heel of Tragedians is a tendency to default to fatalism. A tendency to accept the past as the model for the future.

The Achille's Heel of Utopians is their incapacity to respect individuals, their hunger for power, and their inclination to let the best be the enemy of the good. They are inclined to destroy everything in their pursuit of perfection.

I am strongly inclined towards the Tragic Vision but, as is so often the case, this is not an either-or proposition. The Utopian Vision is an emotional vision and is part of that great desire to improve. We need the Utopian Vision, but in very small doses. We need the Thomas Paine's of the world as long as they are balanced with the Adams, Jeffersons, Monroes, Jays, Franklins etc. We need perhaps one utopian to every ten tragedians.

The problem is that, inherent in the Utopian vision, is the assumption that Plato's Philosopher Kings have the right and responsibility to impose a design on everyone else. Utopianism is inherently totalitarian. Tragedians can accept at least some small number of Utopians but Utopians can only accept Utopians.

In an ideal world we might have the Utopians painting the picture of what could be but would leave it up to the Tragedians to actually consensually implement. In the real world, whenever the Utopians gain the reigns of power, they always destroy everything they touch in pursuit of chimerical perfection.

Tragedians are prone to the full array of human failings but at least their failures are individual rather than imposed on all.

The Utopians have been gaining ascendancy in the West for the past fifty years but now seem to gradually be being repudiated by the citizens of the West. We might, perhaps, be swinging back to the Tragic Vision. That is a good thing, in my view, but we need to be careful not to lose the one good thing that the Utopians offer: aspiration towards a better world.