The comment about the babies is code for evolution.
If evolution has equipped us with the type of mind that survives hostile environments, it may well do so because it provides those minds with the means of understanding reality, even ultimate reality.
A basic premise of materialism is that there is no mind -- no large, imposing knight in the forest -- behind it all. It (whatever it is) doesn't care. So who we are as beings that survived the hostile environment that *it* is, may provide us with a uniquely useful approach to *it*.
The point you mention is that there is not necessarily a connection between the way our minds work and what ultimate reality *is*. But, it may be the case that there is a necessary connection between the two. That simply is a distinct possibility, and evolution would actually be the best explanation as to why that would be the case -- because it would provide survival value. Survival means that you can negotiate your environment; and, for beings like us, that means understanding what we see so that we may alter our response set.
But, as Phaedrus pointed out before, you are positing a kind of Platonic ideal behind the world with this -- the idea that there is an ultimate reality. We speak of it all the time here, but when you get down to it, does that idea really make any sense except as a projection of the way our minds think?
There may be no cave from which we need to escape. Or, even if there is, it would necessarily be the case that we couldn't even see the walls -- we would experience those walls as something in our environment. We can see only what is here and available to us. We are necessarily stuck by our own boot-strapping, but that does not mean that we cannot progress in knowledge about what we describe. Just look around -- we've progressed from turtles all the way down to vibrating bits of energy assuming different harmonic forms.
In a sense, it doesn't make sense to speak of *ultimate reality*. That is why so many folks say that metaphysics is a waste of time. Those who are new to the site who hear that message immediately assume they are speaking to philistines who couldn't think their way out of a box. But some of the folks here, as I'm sure you know full well (and I don't consider myself one of them since I'm still trying to learn all this stuff), are highly philosophically sophisticated and simply don't want to mince words.
Look, for instance, at Darat's and Paul's short replies. They capture the whole argument in a few words. Their replies are not unsophisticated. They hit exactly Rorty's position -- what difference does it make? That sounds trite, but it is actually pretty important when you look further into monism. If we haven't solved a problem in 2500 years there may be a very simple explanation -- the 'problem' is either unapproachable or is not a problem at all. The 'problem' (as in *ultimate reality*) may simply be a word game.