system
Given the following post, respond as if you're commenting on Reddit:
human
Why is it so difficult to interpret the works of philosophers from the past?

In other disciplines, students don't often read the texts where the ideas they are learning about were first expressed (e.g. in physics, students learn mechanics from a textbook rather than Newton's Principia). There is a sense that what the author meant in their original text can be better expressed in a modern textbook, and there is no worry that the process of doing this distorts the original idea. In Philosophy, by contrast, there's an entire field that has to do with interpreting Kant (for instance), and you couldn't teach a Kant class primarily through the use of a textbook and/or other secondary sources. Why is it that philosophers are worried about how to correctly interpret Kant's ideas, but people working in other disciplines (particularly the natural sciences and economics) are not worried about how to correctly interpret the ideas of their great thinkers?
gpt
The question in the title of the post is different from the question at the end of the post. Let's go with the latter.

There's not going to be a single decisive reason for why we value the history of philosophy. Frankly, some people doing philosophy don't care about the history, and some are vocal about it. 


Very often someone interested in what Kant says will be so interested because they think Kant is a smart guy dealing with interesting questions, and he might well be right about the matter at hand; maybe something else he says shows a really good grasp of some philosophical problem, and so you think his work is promising. But there's a part of it that's tricky because his wording's unclear, or he hasn't connected some dots explicitly for you. But you're a professional philosopher so you're pretty much obsessed with the questions Kant's asking and you'd really like an answer. So maybe you spend a few months thinking about Kant on the good will, or something. 

Other times people will say that the history of philosophy is intrinsically valuable. Nobody objects to historians studying the Persian Wars, for example, just because that's not answering some philosophical question. And nobody objects to someone studying Shakespeare's work. Historians of philosophy study intellectual history perhaps for the same reason that people study ancient Greek history or Shakespeare: because they just like knowing stuff about something they find interesting. It's so much easier to not be bothered by "why does the history of philosophy matter?" if you take the history of philosophy *as history*, considering that history departments basically never have to justify their existence.