I was not talking about human's meaning or purpose, but God's.
You can't demonstrate that there is 'god', let alone make specific claims about its purpose... but if, say, God has a purpose, who imposed it upon him? If you can conceive that he did it himself, why can you not accede that we could do the same without gods?
In terms of evolutionary development it is hard to see why humans acquired such abilities as abstract thought processing
No, it's not - they are an inevitable emergent side-process to the complex visualisation and linguistic capacity we developed to be tool users and socially communicative.
...but from a spiritual perspective they are needed in order for us to know God.
There's no rational definition of 'spiritual', no evidence for spirits or gods - why fall back on this spiderweb of conjectural hypotheticals rather than look at what's actually demonstrably there: people.
And we need to look outside the scientific box to discover that there is (divine) meaning and purpose to our existence.
So we don't look with science, which brings us back to an old favourite; where do we look? What methodology other than 'I really, really, really want what my ancestors really wanted to be true to turn out to actually be true' do you propose? Faith is unrealiable, and for those of us with any sort of logic-dominated thought processes 'just want it to be true' isn't enough.
O.