I studied philosophy for 7 years at the undergraduate and graduate levels. But I had a specific intention in mind.
The vast majority of philosophy is garbage, not worth the paper it is printed on. I couldn’t care less what Aristotle’s ethics consist of or what Hume said about causation. Who cares? Some people might think there is an inherent value to knowing the “classics” and educating oneself on the works of so-and-so thinker. Not me. It’s a waste of time… at least in one sense.
But, in another sense, there is value. I am interested in Aristotle’s ethics, not because that topic has value in and of itself, but because Aristotle’s ethics influenced the thought of Augustine and the thought of Augustine influenced the thought of Descartes and Descartes influenced Sartre and Sartre influenced the cultural milieu in which we find ourselves, one that, unfortunately, opposes religion and specifically a religion like Islam.
When, for example, the hijab is discussed as “objectifying” Muslim women, where does this idea come from? Well, people might not know the genealogy, but it was Sartre, among others, who discussed the “objectifying gaze” and, of course, Sartre had his influences and so on. If you don’t know that history and you don’t understand how it’s all connected, you won’t be able to critique that idea, defend the hijab, etc. You won’t be able to address the issue at its root. Or, even worse, you might just take “objectification” as a concept for granted and never even question its relevance or importance to the issue at hand. This is bad.
So, yes, some Muslims should study philosophy if they have the right intention going into it and have a firm, substantial footing in the deen and will be actively studying the Islamic sciences at the same time (not necessarily full-time, but something real, with a traditional scholar, learning and practicing the fundamentals of Quran, aqidah, fiqh, hadith, etc.). Those last two conditions, i.e., substantial footing in and studying of deen, are important because those are your compass. There is no point in setting off exploring this dark sea of philosophy without knowing North from South. You will drown, as have many others who have set out on this journey.
Two philosophical topics that are relatively safe for all to study is logic and rhetoric. As I have mentioned many times on this page, these are basic necessities for effective communication and being a competent, well-informed human being. A big reason someone like Trump (or Obama or any other politician at the national level) is able to gain so much popularity is that people can’t evaluate claims. They can’t hear/read a claim or an argument and understand it and judge it on its own merits. Someone like Trump is well aware of this, which is why all his claims are based on emotions and prejudices. If you don’t understand what a logical fallacy is or what logical validity entails, you are walking on thin ice. If you can’t see the structure of an argument and break it down into premises and conclusion and know how they are connected, you might as well turn off your internet and never comment on anything you read online ever again. In fact, consider this a public service announcement.