What is "spirit"? How would an atheist define it? Does it exist?

Some of the dictionary definitions:

a. The vital principle or animating force within living beings. b. Incorporeal consciousness.

Apparently, some make no sense to an atheist ("Holy Spirit"), but some may ("the fundamental, emotional, and activating principle of a person; will")

http://www.thefreedictionary.com/spirit

What is it?

The word "spirit" in both English and Hebrew both derive from "breath". In primitive thinking, something breathing is somehow magically alive and has "spirit". Christianity has used "soul" for this concept.

While living creatures are certainly miraculous, there is no evidence that what we think of as our identities survives the death of the brain. There is no evidence of the supernatural.

So atheists tend to avoid words like "spirit" and "soul" unless it's very clear the context is metaphorical or it's clearly one of the non-woo-woo meanings. For example, I sometimes enjoy a fine spirit after dinner.

How about these 3 definitions:

a. The part of a human associated with the mind, will, and feelings: [as in] "Though unable to join us today, they are with us in spirit." b. The essential nature of a person or group.

12. The actual though unstated sense or significance of something: [as in] "the spirit of the law".

http://www.thefreedictionary.com/spirit

Do they make sense to an atheist? If so, is "spirit" real as in

a. Being or occurring in fact or actuality; having verifiable existence [http://www.thefreedictionary.com/real]

There is, definitely, something that sets humans apart from stones and trees - the ability to set and achieve goals, overcome obstacles, change and create material reality and ideas. Something that allows some people, businesses, nations, etc. succeed and survive where others fail or die. What's the difference between an alive frog and a dead frog? Both are made of the same matter. What is it? Is it real? If not, what sets the former apart from the latter?

How do atheists explain these questions?

DB: "While living creatures are certainly miraculous, there is no evidence that what we think of as our identities survives the death of the brain. There is no evidence of the supernatural." [end of quote] Does Steve Job's identity survive the death of his brain? Ideas, certainly, have this ability. iPhones are still being produced and Apple stock still goes up. Are our ideas/desires/values, etc. a part of our identity? If so, then it appears that certain aspects of our identity do survive the death of the brain. What are these aspects? Are they real? Do they objectively exist? What do these aspects have in common? Shall we say, they all represent the "spirit" of the person/business/nation, etc. or shall we find some euphemism?

I think your first two definitions would make sense to atheists as metaphorical.

The concept of "spirit" is real in the sense that when we talk of the "spirit of the law", the concept exists in many peoples' minds and it has a similar meaning. That said, I would be suspicious of any attempt to try to define something supernatural into existence.

As for what sets humans apart from trees and dead frogs, humans are alive and have a conscience. A mind.

The say "mind" is what a brain does. There is no evidence that a mind exists without a functioning brain. So when the brain dies, so does the mind.

Concerning your question about Steve Jobs. His memory lives on. Our concept of him lives on. He's not around to be tortured by some fiendish god. He's gone.

Because "spirit" is so intertwined with these woo-woo concepts, it might be better for atheists to use different terms, especially in a context where someone might read some sort of supernatural explanation into it.

DB: "The concept of "spirit" is real in the sense that when we talk of the "spirit of the law", the concept exists in many peoples' minds and it has a similar meaning [...]" [end of quote - clipped not to distort the meaning but to emphasize the part relevant to the reply below.]

We need to be **really** careful with the word "real". Can something existing only in our minds be called "real"? Can it be even called "existing"? Can concepts be "real" given that they only exist in our mind? If we define reality as something existing independently of our mind, any concept cannot be called "real". And if we call concepts "real", we must admit that they exist independetly of our mind. If none of these sound right, then the preposition is false, and reality is not something existing independently of our mind.

We may argue that some concepts describe "reality", whatever it means, accurately, and some do not. We can judge if a concept describes reality accurately using our experience. But if we read the previous sentence again, "judging", "verifying", "experiencing" and "collecting evidence" is something that "mind" and "brain" do. So, no verification or evidence are possible without mind and without a functioning brain. The only undoubtful statement in this blibber-blubber is "I think, therefore I am" (according to Britannica, this is attributed to Descartes - http://www.britannica.com/EBchecked/topic/124443/cogito-ergo-sum). This is the ultimate proof of existence of our mind. Without mind, we wouldn't be even contemplating this nonsense. ("I AM" also happens to be the name of the Lord according to "Exodus" - just a side note without any implications).

DB: "The say "mind" is what a brain does. There is no evidence that a mind exists without a functioning brain. So when the brain dies, so does the mind."

... so does reality. Without mind, there can be no evidence anything exists. So, what does exist "independently of our mind"? And how can we verify its existence? We can kill a brain and see if things still exist. And they will until we kill our own brain. Then we will see nothing. And if we kill all brains we know of, how can we make sure there are no other minds in the universe to spoil our experiment?

Oh, bother... I don't think, our feeble minds will ever find a way out of this nonsense. The only thing left is to grab onto something, accept it as a truth without verification (as in "believe") and build our sanity on that. Note that the truth can be quite arbitrary. But, depending on which "truth" we pick, "results may vary". We may build quite different "realities" and have totally different experiences.

Another note is that immaterial things do seem to exist, at least, in our minds, which is as good as anything for all practical purposes. And they happen to be a part of the reality as it is reflected in our minds.