The fact that mankind arose from such humble fibre as an Odd Little Primate, is the biggest miracle of all. How can good be defined as anything more or less than this. Good is anything that has the effect of insuring the survival or prosperity of the species in part or as a whole. Bad is anything that has the opposite effect. A cultural or religious definition of good and bad has no meaning at all.
Cultures rise and fall, religions continually redefine themselves with every generation.
There is a truth, that can easily be found. It is self evident. Every honest human instinctively knows it. It is not dictated by religious or cultural bias, although it might be reinforced by them. These are the seven basic truths.