Those are great questions that we can discuss. If you are interested, start a thread and I will join in. Not related to this thread, though.
Well, it is related to this thread. You asked what spirit is.
spir·it
: the force within a person that is believed to give the body life, energy, and power
: the inner quality or nature of a person
: a person
My answer, as well as a few others posted, are relevant to the question, as commonly defined by Merriam-Webster at least.
Is any person defined only as a body and substance that is measurable or is there something immaterial that makes them "who" they are?
Full Definition of SPIRIT
1 : an animating or vital principle held to give life to physical organisms
2 : a supernatural being or essence: as a capitalized : holy spirit b : soul 2a c : an often malevolent being that is bodiless but can become visible; specifically : ghost 2 d : a malevolent being that enters and possesses a human being
3 : temper or disposition of mind or outlook especially when vigorous or animated <in high spirits>
4 : the immaterial intelligent or sentient part of a person
5 a : the activating or essential principle influencing a person <acted in a spirit of helpfulness> b : an inclination, impulse, or tendency of a specified kind : mood
6 a : a special attitude or frame of mind <the money-makingspirit was for a time driven back — J. A. Froude> b : the feeling, quality, or disposition characterizing something <undertaken in a spirit of fun>
7 : a lively or brisk quality in a person or a person's actions
8 : a person having a character or disposition of a specified nature
9 : a mental disposition characterized by firmness or assertiveness <denied the charge with spirit>
10 a : distillate 1: as (1) : the liquid containing ethanol and water that is distilled from an alcoholic liquid or mash —often used in plural (2) : any of various volatile liquids obtained by distillation or cracking (as of petroleum, shale, or wood) —often used in plural b : a usually volatile organic solvent (as an alcohol, ester, or hydrocarbon)
11 a : prevailing tone or tendency <spirit of the age> b : general intent or real meaning <spirit of the law>
12 : an alcoholic solution of a volatile substance <spirit of camphor>
13 : enthusiastic loyalty <school spirit>
14 capitalizedChristian Science:god 1b
http://www.merriam-webster.com/dictionary/spirit
Your question seems very specific in terms of definition, where only #2 and #14 seem relevant. Of course, these are by nature, subjective and open to interpretation and belief. Good luck with getting any answers that are satisfactory from a scientific perspective. Of course, none will be.
Which makes this thread less than genuine and sincere if you have no interest in answers given to such an philisophical question.