From the scientific view, the theory of karma may be a metaphysical assumption -- but it is no more so than the assumption that all of life is material and originated out of pure chance
Dependent Origination is the teaching (that life) is not the mere play of blind chance, but has an existence that is dependent upon conditions. That, precisely with the removal of these conditions, those things that have arisen in dependence upon them-thus also all suffering-must perforce disappear and cease to be.
Delusions are states of mind which, when they arise within our mental continuum, leave us disturbed, confused and unhappy. Therefore, those states of mind which delude or afflict us are called 'delusions.'
O youth or young man, who fancy that you are neglected by the gods, know that if you become worse, you shall go to worse souls, or if better to the better... In every succession of life and death, you will do and suffer what like may fitly suffer at the hands of like. This is the justice of heaven.