This is not a specific speach. It is anything of the form:
If X, I desire to believe X.
If NOT X, I desire to believe that NOT X.
Let me not become attached to beliefs I may not want
When used at solstice, usually it is recited several times, beginning with innocuous Xs like “The sky is blue” or “The earth is a sphere” and working up to “I should abandon my plans” or “We are all going to die”. There can also be a metalitany, where X is “reciting the Litany of Tarski is helpful”. The metalitany can be recited in a modified form:
editIf reciting this litany is helpful, I desire to recite this litany.
If reciting this litany is not helpful, I desire not to recite this litany.
Let me not become attached to habits I may not want.