I didn't say it currently exist, but believing in advancement constitutes this no?
If you'd let me be pedantic, (And I'll be pedantic whether you let me or not )
Saying a higher being exists would imply it currently exists. Kind of like when deists saying a God existed but now is either gone or doesn't care about humans. Under that assumption even if there was a deist God and it was the only thing "greater" than humans, now there would be nothing greater that exists.
(I don't hold the opinion that humans are the "greatest beings", I'm just ironing this issue out)
"We swallow greedily any lie that flatters us, but we sip only little by little at a truth we find bitter." ~ Denis Diderot