One of the terms that atheists often apply to themselves is the term "skeptic". Skepticism is defined as the disposition not to accept claims without proof – to be skeptical that a claim is true unless and until one has been provided reason to believe it. The skeptic, when presented with a new proposition, adopts a default value of "false" and only switches the value of "true" to that proposition when proof has been provided.
Furthermore, skepticism is supposed to be a virtue. It is a quality that a good person would have.
Using desire utilitarianism, a disposition to give a value of "false" to any new proposition is claimed to be a disposition that people generally have reason to promote. It says that people generally have reason to inhibit (through condemnation) those who accept claims too easily. Gullibility, in other words, is a vice.
All of this can well be true. However, there is a form of skepticism (or a degree of skepticism) that is contrary to these claims.
This is a paralytic form of skepticism that prevents a person from acting because the person cannot know what the results of his actions will be. He cannot deal with the fact that the best that he can come up with on a given evidence is a conclusion that is the best possible conclusion on the basis of available evidence – that this is what one must act on, even if there is a possibility of error.
Granted, this form of skepticism is typically used as a rhetorical claim by somebody who wants to obstruct the actions of others. Somebody proposes a particular course of action that the agent, in this case, does not like. One of the tactics that this agent can adopt is that of skepticism. “We do not know what the results of these actions will be. Therefore, we must do nothing. We cannot act without certainty. We cannot act until the evidence is in.”
Exxon-Mobile and the other global warming profiteers, Phillip Morris and the cancer profiteers, and any number of 'skeptics' of government policy fall into this camp. They are skeptics by convenience, declaring “we cannot know, so we cannot decide” then they are in a position to profit from the misguided decisions that people make based on the ignorance (the 'skepticism') if the masses.
We see it in all sorts of debates and discussions when somebody wants to block movement in a particular direction
We have to accept the fact that sometimes limited evidence (or information) has be enough to act on. It may not be perfect information. It may not be sufficient to convince the agent to know what the best course of action is.
We all do this all the time. It is no fair criticism against a person that he is acting on incomplete information, just as there is sometimes fair criticism to be made of a person who will not act on the basis of poor or incomplete information no matter how much of that information he obtains. His goal is to block progress – to be an obstructionist – and he uses skepticism as a tool for building obstructions.
This type of skepticism is no virtue. It's a form of manipulation, much like lying. Those who employ this technique seek to hijack the will of others and to take the products of their efforts for one’s own, by manipulating them into acting in ways that are not in their benefit.
This form of skeptic needs to be met with the claim that, "We have information enough on which to make a decision. Unless you can come up with positive reason to believe that we should not commit the act, then it is perfectly reasonable for us to act."