**Short Answer** In a broad brush, at the heart of the difference between your comparison between the mathematical method and the philosophical method (whatever they may be) is embedded an analogy about language use. I would respond that it is a [false analogy][1]. Mathematical computation is fundamentally easier to understand and verify than natural language argumentation. **Long Answer** The primary difference between mathematical texts and philosophical texts is that mathematical texts approach theory building in a much different manner than philosophical texts on account that math is generally a [deductive process][2] built on an [artificial language][3] which uses a [truth-conditional semantics][4] whereas philosophy is built on [defeasible reasoning][5] including [abduction][6] using [natural language][7] using theories of semantics that look to be [comprehensive by using conditions including but beyond truth conditions][8]. So, when Newton uses math to prove a theorem, and that theorem has been vetted for centuries the meaning of that theorem is rather indisputable. Its meaning is as consensual and clear as a meaning can get since mathematics uses a clear set of symbols and axioms when creating [well-formed formulas (WFFs)][9]. In fact, WFFs are so consistent and unambiguous, that their usage can be formalized and automated such as those used in [formal languages][10] and [automata][11], the latter being a class of mathematical objects which includes the [Turing machine][12], the essence of a computer with a [von-Neumann architecture][13]. Natural language and the defeasible reasoning in philosophy simply can't be reduced to the same [formal system][14]. Since this is the case, meaning is much more difficult to establish, agree upon, and verify. Whereas in the Netwon example, mathematicians the world over and can look at the calculations and agree, the same cannot be said from a passage from Wittgenstein translated to English and partially cited in the context of an argument. The relevant concepts in linguistics are [paraphrase][15] and [metaphrase][16]. In fact, the very nature of what constitutes the equivalency of [propositions][17] is quite a philosophical problem in and of itself and is naturally a function of your [philosophy of language][18]. One prominent term used in conjunction with the study of [synonymy][19] is Noam Chomsky's [deep structure][20]. So in summary, the importance attached to the original propositions of the original texts is held generally by philosophers because of the [ambiguity][21] that inheres in natural language. Ultimately the nuances of language, whether those of [implication][22], [implicature][23], [connotation][24], and [denotation][25], are even complicated by figurative language such as [metaphor][26]. This is precisely why mathematicians insist on using formal symbols stripped of ambiguity, and undermines the idea that one can do the formal computation of mathematics (we are, of course, neglecting mathematical philosophy) and [informal logic][27] used in philosophical argumentation in the same way. [1]: https://www.thoughtco.com/false-analogy-fallacy-1690850 [2]: https://en.wikipedia.org/wiki/Deductive_reasoning [3]: https://en.wikipedia.org/wiki/Artificial_language [4]: https://en.wikipedia.org/wiki/Truth-conditional_semantics [5]: https://plato.stanford.edu/entries/reasoning-defeasible/ [6]: https://plato.stanford.edu/entries/abduction/ [7]: https://en.wikipedia.org/wiki/Natural_language [8]: https://en.wikipedia.org/wiki/Metasemantics [9]: https://en.wikipedia.org/wiki/Well-formed_formula [10]: https://en.wikipedia.org/wiki/Formal_language [11]: https://en.wikipedia.org/wiki/Automaton [12]: https://en.wikipedia.org/wiki/Turing_machine [13]: https://en.wikipedia.org/wiki/Von_Neumann_architecture [14]: https://en.wikipedia.org/wiki/Formal_system [15]: https://en.wikipedia.org/wiki/Paraphrase [16]: https://en.wikipedia.org/wiki/Metaphrase [17]: https://en.wikipedia.org/wiki/Proposition [18]: https://en.wikipedia.org/wiki/Philosophy_of_language [19]: https://en.wikipedia.org/wiki/Synonym [20]: https://en.wikipedia.org/wiki/Deep_structure_and_surface_structure [21]: https://en.wikipedia.org/wiki/Ambiguity [22]: https://en.wikipedia.org/wiki/Implication [23]: https://en.wikipedia.org/wiki/Implicature [24]: https://en.wikipedia.org/wiki/Connotation [25]: https://en.wikipedia.org/wiki/Denotation [26]: https://en.wikipedia.org/wiki/Metaphor [27]: https://en.wikipedia.org/wiki/Informal_logic