It is now mandatory to doubt. To claim to know anything with certainty is to fall foul of dogmatism, the stubborn refusal to subject beliefs to any test for truth. But is certainty the same as dogmatism? And isn't the demand for universal doubt merely another form of dogmatism?
First, to the latter point. It seems that to demand doubt is to assume a universal knowledge claim - something like: it is not possible to be certain of the truth of any belief, or, no human being can be certain of any belief, or even, no belief can produce certainty. Such claims, although different, have the added premise that no person should have certainty and that every human being should hold every belief with some degree of doubt.
A word should be said about certainty at this point. In this context certainty implies the absence of doubt. Sometimes the word is used in degrees - to obtain an amount of certainty to do with how probable that a belief might be true. That is not what is meant by those who object to certainty and believe that doubt is obligatory for all human beings.
Is certainty the same as dogmatism or does certainty somehow entail dogmatism? I don't think so. For the following reasons: First, it appears that there is nothing irrational in the belief that it is possible that a human being believe something that is true (in the corresponding to reality sense). And if this is not an irrational belief it seems hard to call this dogmatism: to be certain that it is possible for a human being to believe something that is true. If one is a Christian, furthermore, we have an example of a human being whose claim to know something for certain appears wholly rational. Jesus Christ, being human and divine, would be able to know truth since, by his divine nature he cannot believe a lie.
Finally, it is hard to see why a person's certainty is to be suspect solely due to the assertion that all beliefs be subject to doubt. That amounts to making doubt the ground floor of life, that doubt is the only thing not subject to doubt. And, as the quip goes, "to choose doubt as a philosophy of life is akin to choosing immobility as a means of transportation" (Yann Martell, The Life of Pi, p 28).