I think, first of all, that you are doing an amazing job in uncharted territory. This small human is not an easy one to raise, but your close observation will help a lot.
Aww, thanks!
Second, the inconsistency between his abilities when watched vs. off-guard suggests it's not a physical issue (as Dude said). To me, especially given his age and the level of philosophical thought you've described before, it sounds like he's holding back in some areas to avoid independence and keep a close, age-appropriate relationship with his mommy. He may not truly believe you will still cuddle and read to him if he reads himself, for instance. He wants to keep a division-of-labor in his daily life that you do part of. He might worry that once he demonstrates an ability, he will have to do it perfectly all the time. He's able to understand the truth - that moving on from a toddler's independence level is a major change, and irreversible. That's going to be scary.
If I'm right, then these thoughts are having a significant life impact and are worth addressing. Mother's Day might be a perfect time to demonstrate that mothers stay in our lives for all our lives. Have a wonderful one!
I think you're spot on. DS has intuited that growing up in these areas is a bell that can't be un-rung, and he's holding onto our current roles while testing the waters of more independence secretly.
He's also keenly aware of mortality. Where most children seem to mentally tackle discrete chunks of time they see ahead in the future and proceed hunky dory, DS seems to be drinking in the entirety of the remainder of his life and anticipating events that will happen 15, 25, or 70 years down the line and his reactions through a 3-year-old's eyes. Yikes! We've talked about how much he will change between now and adulthood, and even in the next year. I've broken out a rough template of what "being 4" entails (spoiler: it's just 3, but with him fully toilet trained and occasionally doing more self-care) to demonstrate that change is an incremental process that only happens when he is ready.
We have a very close relationship, so I'm continuing to offer the comfort he's always sought (through nursing, cosleeping, lots of cuddles and silly free play, etc.) as an anchor to keep him grounded during all his internal development. If anything, I think I'm going to ratchet up our rough housing, sports, and silly play, because that connection helps him blow off steam and will continue to be age-appropriate pretty much indefinitely!
