Quotations about:
    break down

… To divide each of the difficulties under examination into as many parts as possible, and as might be necessary for its adequate solution.

[… De diviser chacune des difficultés que j’examinerais, en autant de parcelles qu’il se pourroit, et qu’il seroit requis pour les mieux résoudre.]

René Descartes (1596-1650) French philosopher, mathematician

Discourse on Method [Discours de la méthode], Part 2 (1637) [tr. Veitch (1850)]
    (Source)

(Source (French)). Alternate translations:

... To divide every One of these difficulties, which I was to examine into as many parcels as could be, and, as was requisite the better to resolve them.
[Newcombe ed. (1649)]

... To divide up each of the difficulties which I examined into as many parts as possible, and as seemed requisite in order that it might be resolved in the best manner possible.
[tr. Haldane & Ross (1911)]

... To divide each problem I examined into as many parts as was feasible, and as was requisite for its better solution.
[tr. Ascombe & Geach (1971)]

... To divide each of the difficulties I examined into as many parts as possible, and as may be required in order to resolve them better.
[tr. Cottingham, Stoothoff (1985)]

Divide each difficulty into as many parts as is feasible and necessary to resolve it.