Ryan Norbauer is pretty sure that:
Not only are all religions manifestly false, but so too are all the secular narratives (humanism, positivism, liberalism, libertarianism) that, like religions, attempt to craft a system of positive values out of the epistemologically questionable notion that something can be transcendently and meaningfully true merely because it would be nice if that were the case. Reasoning by appeal to platitude or an implausible alternate-universe utopia is not reasoning at all. These facts may not delight us overmuch; they are still true.

Of course I agree with the religious part of that statement. Yet he also kills off humanism. I'm certainly not the kind of gung-ho replacement-religion humanist like Greg Epstein, but perhaps whatever humanism appeals to is better than the alternatives for society as a whole, even if an individual need not believe in any narratives.

And I'm not sure if humanism is a narrative. Of course, I'm not really a scholar in humanism--my Renaissance Man development is at the early stage of Renaissance Boy. I.e., I don't go around claiming to be a polymath, but I claim to strive to be a polymath.

Certainly transhumanism is a narrative of the future--really several stories. A lot of transhumanists convert science fiction into prophecy and follow it religiously, thus reducing it to Norbauer's description. Should we instead look to narratives of the past?

"Welcome to the twentieth century, out of which your century grew as surely as a column of black smoke grows from an oil fire."
--Clive James

In the book Cultural Amnesia, Clive James wrote about how few philosophical thinkers in the nineteenth century would doubt that the extension of human knowledge, primarily through science, would produce a race of the enlightened to lead a life of "mathematically calculated justice."
By now, after the twentieth century has done its cruel work, that is exactly what we doubt. The future of science, Renan's cherished avenir de la science, can be assessed from our past, in which it flattened cities and gassed innocent children: whatever we don't yet know about it, the thing we already know is that it is not necessarily benevolent. But somewhere within the total field of human knowledge, humanism still beckons to us as our best reason for having minds at all.

Poetic, but is humanism a reason? I suppose if we want to maintain civilization and culture then it is.
Learned books are published by the thousand, yet learning was never less trusted as something to be pursued for its own sake. Too often used for ill, it is now asked about its use for good, and usually on the assumption that any goodwill be measurable on a market, like a commodity.
If humanism that makes civilization civilized is to be preserved into this new century, it will need advocates. Those advocates will need a memory, and part of that memory will need to be of an age in which they were not yet alive.

Perhaps what transhumanism should be is less of a cult of cults pretending that various science fictions are true and more of a science patch to humanism. Humanism already included science and learning in general. So the patch is not to add science, but to fix its use and expectations in culture. To advance by tuning the dangerous oscillations out of the civilization-science feedback system.