A couple of days ago the following idea caught my eye in a book review, the reviewer recalled Nietzsche as having said that in order to test a philosophy you should find out whether you can live by it. He argued that this is the only way to critique a philosophy and to prove something. I was first taken aback by the simplicity of the method but when thinking about it realized that I found it quite an attractive proposal.
Im not sure I fully get his idea because these one-liners usually allow for more interpretations than the author intended but the idea as it seems to me would be expressed in taking a philosophy or way of life and trying to live according to it for a certain time.
There are some problems with this approach because if for example a person were to test a very ascetic form of Buddhism which involves self-flagellation it is probable that he or she would be able to conclude within a short time span that this philosophy is very flawed, but for a person who is attracted to those types of expressions it might be very fulfilling. So there seems to be a very strong element of subjectivity in it. Perhaps Nietzsche’s idea was narrower than this, perhaps he proposed this as a complement to theoretical inquiry instead of a substitute thereof.
Nevertheless in broad lines I think it can serve as a helpful way to look at a philosophy. I personally have found it very useful to try to live certain ideas, some of which confirmed their truth- and usefulness, while others turned out to be less so and therefore were rejected or subjected to greater investigation, before persisting in them.
An example of this would be fixed prayers. I used to think that these were a detriment to a prayerful life and lacked any sense of meaning. The first time I tried it, it was somewhat confirmed but when I persisted in them, I slowly started to see their efficacy and have now come to a point where I can hardly live without them.
It seems we often act like our beliefs and ideas are all based on strict logic and that we wouldnt engage in something we havent arrived at rationally, but actually we often also employ reasons that are not wholly rational. Take the idea of prayer, if one would before engaging in it deliberate about its use and efficacy, in the face of the idea that God is unchangeable and the many unanswered prayers, it would seem to be considerably more difficult to get up everyday and utter prayers. But the fact is that many, including myself, do. While I certainly dont deny the idea that God is unchangeable or the seeming gap between demand and supply I do manage to wake up everyday and pray.
And while its difficult to discern all reasons, rational and irrational that play a part in this decision (which essentially assents to the idea of prayer), I do think much of it is based on the fact that it seems to work for me, I can live by it, and it is helpful.
Im sure there are exceptions to this theory but in broad lines I think it could be [and in many cases is already] a good complement to theoretical inquiry.

