Sixth, conservatives are chastened by their principle of imperfectability.
"Human nature suffers irremediably from certain grave faults, the conservatives know. Man being imperfect, no perfect social order ever can be created. Because of human restlessness, mankind would grow rebellious under any utopian domination, and would break out once more in violent discontent—or else expire of boredom. To seek for utopia is to end in disaster, the conservative says: we are not made for perfect things. All that we reasonably can expect is a tolerably ordered, just, and free society, in which some evils, maladjustments, and suffering will continue to lurk. By proper attention to prudent reform, we may preserve and improve this tolerable order. But if the old institutional and moral safeguards of a nation are neglected, then the anarchic impulse in humankind breaks loose: 'the ceremony of innocence is drowned.' The ideologues who promise the perfection of man and society have converted a great part of the twentieth-century world into a terrestrial hell."
Taken from the Russell Kirk Center.