The idea behind this title is not the block as a block, since one can write whatever comes to their mind. However, the writer’s block exists in terms of creativity and ideas flow.
In philosophy writing, a block can be undone by starting with definition and analysis of the main concept (or concepts). It ensures a depth of the writing without passing by some ramblings found here and there to add more lines/pages. Added to this, and it is the most important part of a philosophical writing ( whether it is an essay or a dissertation or even an explanation of a text) is the questioning part. That’s the real philosophical exercise; otherwise it will be just a presentation.
Then, one can get inspired from other writers or philosophers in case of a philosophical essay. Perhaps quoting some of their paragraphs or even comparing them to other thinkers/philosophers/writers (all depends on the content to be delivered). Not to forget to keep the questioning going.
In conclusion a writer’s block exists in terms of depth and analysis.