“The hole left by the Christian dark ages”

This chart is horseshit.

It’s horseshit logic based on horseshit history.

As a history of science, it’s glaringly bad.  Since the scientific method wasn’t really developed until early modern (Christian) Europe, let’s assume “scientific advancement” means philosophical and technological  innovation.  There was no precipitous drop to barbarism in the fifth century (and little disruption in the “Byzantine” Roman east).  Western Europe suffered the collapse of infrastructure, but monasteries preserved classical learning until church-supported universities began to thrive in the early second millennium.  Along the way medieval Europeans gained wind and water mills, spectacles, rudders, and a host of other inventions Augustus didn’t dream of.

Europe in 400 CE was not equal in “scientific advancement” to Europe in 1600.

But suppose the chart was completely accurate: what does it prove?  That religion is harmful?  That’s unlikely–learning flourished under early Islam (another problem with the chart–it ignores everyone but Europeans).  Is it that Christianity in particular is bad for science?  That’s hard to argue, given that Christian civilization produced Galileo and Newton.

As an alternate history (“What if there was no ‘hole’?”), it’s hackwork.  Before Rome, states had risen and fallen for thousands of years and none had taken this exponential trajectory.  By 400 Rome was already fracturing for reasons unrelated to Jesus.  Even if it weren’t, widespread slavery dampened the demand for labor-saving technology, and classical thinkers shunned physical experiments (manual labor!) in favor of thought experiments.

One final note: when Christians invented steam engines, they used it for pumps and looms and locomotives.  The ancient Greeks used theirs to wow the masses with fake miracles.