Philosophers, like many others, are threatened by disagreement. You can tell because we expend as much effort avoiding disagreement as we do addressing it—determining criteria for justifications and for knowledge, and standards for what counts as ‘legitimate’ disagreement. All these limitations and exclusions are intended to settle disagreements before they start, by determining in advance what disagreement must be about if it is to be taken seriously. However, to unilaterally decide what disagreements are legitimate is to refuse to take disagreement itself seriously at all.
Disagreement can be about anything, and on any basis. This is why philosophers, no stranger to doubts and searching enquiries, are threatened by disagreement. Your doubts are your own, and invariably concern matters that you consider worth attention, but disagreements are with others. They arise out of the questions and concerns of others, and so they don’t need to match, or even be compatible with, your own.
I argue for an approach to disagreement and to criteria that does not foreclose disagreement, but tolerates leaving matters open. Instead of limiting controversy by determining in advance what constitutes adequate justification or what conditions a belief must fulfil if it is going to be a candidate for truth, an anti-dogmatic philosophy must consider its founding positions and perspectives part of what is open to discussion, what is up for debate. To do so is not to resort to scepticism, it is to resist intellectual arrogance.