Scientific knowledge versus spiritual knowledge

[Vincent]

Are we justified in believing in human value?

I'm confused by your use of the word "justified". Just because we are "justified" to believe whatever the hell we want (i.e. believing that the universe was created by a unicorn simply because that's what you think happened), doesn't always mean it's objectively true. Human life has value only to humans. Objectively speaking, it doesn't have value. In fact, the entire concept of "value" is subjective. In the eyes of other animals and life forms with whom we share this planet, we have no value at all, and most of them would be pleased to see us wiped off the Earth. Human life has value to us because we are humans. The planet and the universe do not care if we are here or not here. No tears would be shed if every one of us were to die tomorrow. From an objective standpoint, human life is rare, since this is likely the only place we exist in the cosmos, but it contains no actual or greater significance. 

But it does to us. Because we feel, and we experience emotion, empathy, and connection to other humans. We care deeply for our lives and for the lives of our fellow man. Because of these things, we attach a great degree of significance to human life. We think it's valuable. Atheists such as myself especially stake value in it, because we understand this is probably the only life we get. But that's our bias. That's not objective. It exists within the realm of our subjective human experience and nothing more. Actual knowledge, and the truth that science seeks out, is objective. It is objective because that understanding exists regardless of whether or not we are dead. Take our knowledge of gravity or mathematical systems for example. Those things are objectively true, and even if we died tomorrow, they'd still be true. Our value, if we died tomorrow, would not be. Because the value of human life is contingent on us being around to say that it's valuable,and it ceases to exists when we do. That's why I do not see spirituality as knowledge. Because it's not. God exists as a figment of imagination in the minds of theists, but not on an objective, measurable scale of real knowledge (at least, none that has ever been proven). Claiming that God exists because you have subjectively and personally experienced him does not prove he exists. When have we ever, in all of human history, gained knowledge of something using this "evidence" and nothing else more concrete and palpable?