The 'mere talk' doesn't have to finish. You can have pretty nebulous ideas, and still start making progress with the formalism. The formalism can even help you 'finish' your thoughts.

In fact that kind of 'finishing' is very important, because otherwise you can waste a lot of time talking without noticing that you are not going anywhere. See eg philosophy or theology or pre-scientific-revolution science (ie natural philosohpy and natural history).