The Logical Atheist

To teach mankind virtue, they are to be presented [by Christianity] with the example of murder; to render them happy, it is necessary to exhibit innocence in distress; to provide for them the joys of Heaven, wretchedness is to be made their portion on earth. To make them love one another, they must be taught that the Deity, regardless of this principle, voluntarily sacrificed his only begotten Son. In fine, to procure for intelligent beings the happiness suited to their nature, cruelty and vindictive malice must be exhibited for their contemplation. This doctrine presented in its true colours contains neither justice nor utility. Its principle is vicious, and its consequences are not beneficial. --Elihu Palmer (1764-1806), Principles of Nature; or, A Development of the Moral Causes of Happiness and Misery Among the Human Species

Another important doctrine in the Christian religion is the atonement supposed to have been made by the death and sufferings of the pretended Saviour of the world; and this is grounded upon principles as regardless of justice as the doctrine of original sin. It exhibits a spectacle truly distressing to the feelings of a benevolent mind, it calls innocence and virtue into a scene of suffering and reputed guilt, in order to destroy the injurious effects of real vice. It pretends to free the world from the fatal effects of a primary apostacy, by the sacrifice of an innocent being. Evil has already been introduced into the world, and in order to remove it, a fresh accumulation of crimes becomes necessary. In plain terms, to destroy one evil, another must be committed.  --Elihu Palmer (1764-1806), Principles of Nature; or, A Development of the Moral Causes of Happiness and Misery Among the Human Species

Magic or religion: it is all one. Theologians themselves dispose of the matter by calling everything they do an act of religion, including even such operations as bedizening themselves with high-sounding titles and dignities, superior to any ever claimed by Christ, and laying taxes upon the faithful for their own aggrandizement; if that is how they feel about it, let them have their way. Their earliest forerunners, we may be sure, wasted no time upon such bandying with words. They were aware of no difference between magic and religion, but practised both with easy consciences.  --H. L. Mencken Treatise on the Gods , 1930

One would have supposed that after having brought temporal death into the world by [Adam and Eve's] transgression, and after having corrupted every moral principle of the human heart, the contrivers of the scheme might have been contented, without annexing to this crime any other fatal consequences; but fanaticism and superstition delight in murder, misery, and eternal fire; and to this flaming lake I wish them a speedy passage, never more to rise to insult the dignity, or destroy the happiness of the human race. To punish the temporary and finite crimes of a finite life with eternal fire, would be to relinquish every principle of distributive justice, and to act like an arbitrary and malevolent tyrant. All the sins that ever have been committed do not deserve this unlimited severity of punishment; and to attribute to one solitary infraction of a moral law these terrible consequences, is to lose sight of infinite benevolence and eternal justice. It is to represent the God of Nature...

[T]his doctrine, called original sin, is, in the first place, totally impossible, and in the second place, that it is as immoral and unjust, as the Creator is righteous and benevolent. The virtues and the vices of intelligent beings are not of a transferable but of a personal nature. In a moral point of view, the amiable or useful qualities of one man cannot become those of another, neither can the vices of one be justifiably punished in the person of another. Every man is accountable for himself; and when he can take no cognizance of the intentions or actions of any other man, how can he be justly responsible for their injurious effects, or applauded for any benefits resulting from them? If Adam or any other man, who lived several thousand years ago, was guilty of an immoral conduct, what has that to do with the moral condition of the present generation? Is a man to become criminal before he has existed? or, is he to be criminated afterwards, by the immoral conduct of those who lived ...

A hardcore skeptic, one that David Hume would call an "excessive," or (unmitigated)  Pyrrhonian , skeptic, would not ask, "How do you know P is true?" Rather he would ask, "Why should I believe anything put forth as evidence for P?" The first question acknowledges the possibility of knowledge and hence is not the question of a philosophical skeptic. The second denies or at least seriously doubts that any knowledge is possible. That is skepticism (in all its self-contradictory glory).

I don't know how I recognize faces I have seen many times before (though specialists may understand this to some extent). But who would insist that since that is the case, I have no grounds confidently thinking that I indeed  do  recognize such faces? Or who would say that until I  do  understand, I should restrain my confidence in my reasonably reliable ability to recognize faces? Gilbert Ryle referred to this distinction as knowing   how versus knowing that . It's a distinction we ignore at our folly.