When my sister had her second child, my mother joked that she’d given birth at the perfect time — giving us a newborn to play with just as the eldest developed beyond the “cute baby” stage. I thought this was a pretty naff thing to say at the time, even though she obviously didn’t mean it. What I didn’t expect was, when confronted with my own bundle of joy, to genuinely feel a longing for the permanence she had jokingly described.

Babies are constantly and rapidly developing, usually according to a surprisingly predictable cycle not unlike a software update release schedule. It’s tempting to treat babies as logic boxes: if the baby is in condition foo and I respond with input bar then he will happily produce output baz, and I will be a Good Parent. Of course the rules will vary depending on what “leap” he’s up to, but there are rules, and so long as I remember to study the rules for this particular leap, they should be easy enough to follow. Right?

Of course that isn’t true. But I have found, in my limited experience, that it’s true enough that reading the “rules” for spherical baby in a vacuum can make a great starting point for learning what your real life baby needs, when combined with close observation and patience. And so to understand our baby’s needs and make sure we’re well-placed to meet them, we have scrutinised and memorised his every movement and built a list of possible expectations from a combination of medical advice and trail and error. When he makes this noise and moves his head against your chest it means he’s hungry, unless he also kicks out his legs, in which case it means he wants to go to sleep, unless he immediately follows it with that noise and blows bubbles, which means he wants to play but needs help distracting him from the pain of teething, unless …

And then a leap occurs and the rules change. But what we’re thinking of as abstract “rules” (or the interpretations of a logic box) are actually the wants and needs of a growing baby, and the changes brought on by the leap are not changes to arbitrary rules, but fundamental changes to the personality of the tiny human we’ve been getting to know better than anyone else we’ll ever meet. The bold, inquisitive explorer who poked his head towards every strange corner of the world and peered dimly ahead in hopes of divining what was out there is now shy, now looking to us to shield him from a world he can now see more clearly, and which must seem terrifyingly large and busy to his inexperienced baby brain. And as we leap through more and more fundamental personality shifts, I can’t help but think about the versions of him that we’ve left behind.

I am beginning to feel that to be a parent, or otherwise closely associated with a newborn, is to pass repeatedly through phases of confusion, reaffirmation, comfort, and loss. Every few weeks we meet our baby anew, and we mourn the one we had just started to understand. I don’t want to arrest his development, and I don’t want to replace him with a younger model, but I do feel the loss of the baby I had known, and I don’t really know what to do with that emotion.

Now, with every leap our baby becomes more complex, more expressive, more a part of this complicated world. And that is undeniably a Good Thing. As cute as he is, I don’t want to spend the rest of my life looking after a three-month-old. And surely the biggest draw in being a parent in the first place is to see your child become the best version of himself. But while that’s all undoubtedly true, I also really quite like knowing the exact places to tickle him for the biggest smiles; the perfect way to hold him to get the best chance of rocking him to sleep; and exactly how much milk to set aside of an afternoon.

It’s exciting to watch my baby develop. It’s one of the coolest things about being a parent. But I can’t help but wish I had a little more time to get to know each version of him before the next advance comes along.