The common excuse is that 'spirit cannot be defined' can be appealing because it can be taken to mean 'spirit is too loafty to define' and who doesn't like 'spirit' enjoying such a status? However, when we close exermine things in general, we soon find that everything has this tendency of posing insurmountable challenge when you try to define. So 'spirit cannot be defined' isn't as impresive as such. Specifically, yes, we can define 'spirit' like we can, everything else and no, we can't define it enough but so can't we, anything else! So we realy have no excuse but to clear confusions.