A philosophy of life - how necessary is it?
Do you mean in theory, or what I actually do?
Because in theory, it is of course very clear. I am mostly libertarian: I believe adults should be free to do what they want provided they harm no one.
In practice, well.
We share the earth with other humans. We need some rules for getting along. Traffic regulations, for instance. I’m ok with speed limits and street lights even when there’s nobody else on the road at 4 am. We need to be able to enforce basic human rights against those who insist on violating them - think of non-discrimination in the workplace or in the housing market. Pure libertarianism would say it’s ok to keep your property men-only or Catholic-free, for instance. But is that really a society we want? Not so clear.
It’s very easy to be pure in theory. But out here in the real world, nobody is pure anything. (Except pure asshole, I suppose. Bu that’s not a philosophy of life you want to follow.)
The trick is to have a clear philosophy that’s well thought-out because it can be useful to have something to fall back on when you’re not too sure how to behave. It’s like a diet. If you’re Paleo you know what to eat and what to avoid, generally speaking. But you will make exceptions for instance if you’re invited somewhere and they added rice to your bacon meatloaf . Yes you’re Paleo and people should know about the rice, but jeez, there’s no need to be impolite and unpleasant about it. Same with your own personal guide for the good life. Don’t be the jerk who’s so invested in his philosophy that he forgets human beings need flexibility and a little wiggle room for mistakes sometimes. We’re all muddling through with no instruction manual down here in the real world.