In order to live properly, one must start by defining one's terms.
One must try to find an objective measure by which to judge the desirability of an action.
On the one hand, objectivity is inherently illusory. Even if you get what appears to be objective data, you introduce subjectivity by measuring it and interpreting it. Obviously you have biases. You would prefer one result to the other. You have unquestioned notions of what is right. Murder is wrong, Altruism is right. Progress is inevitable. There is One True God.
On the other hand, we need rules and assumptions in order to take efficient action. To submit fully to the impossibility of fully knowing is to render oneself superfluous. Nihilism or nirvana. I am not prepared to give up suffering or desire. But I want to limit the harm I cause to others.
So I have taken these things on faith:
That compassion is virtuous.
That slow is usually better than fast.
But not always.
That every living thing is lit by a spark of divinity.
That every living thing should be treated with consideration and dignity.
And probably inanimate things as well.
That all experiences are valuable.