Thanks Brexit, for making the process of ordering and receiving a replacement for an aging peripheral so exquisitely painful. In the old days, goods moved from the UK to other EU countries effortlessly. Now, their transit resembles an Odyssean epic straight out of Greek mythology.

• Day 1. Place the order. Get an email from the merchant, asking if I’m really sure I want to proceed with the order, given that I’m going to have to pay import duties when I receive it (and they want to avoid me returning the item when I find out how expensive and painful that’s going to be). Confirm my willingness to run the gauntlet, and see exactly how deep the rabbit hole goes.
• Day 2. Receive notification from DHL that the order is on the way, with an estimated delivery date 7 days in the future.
• Day 3. Order arrives in my country.
• Days 4 and 5. A weekend. All quiet on the Western Front.
• Day 6. Order arrives in my city.
• Day 7. Order shows as "detained", but status page notes that DHL will contact me to obtain details necessary.
• Day 8. Order still shows as "detained". Given that DHL hasn’t contacted yet, I contact them. Receive email from DHL asking me to fill in an authorization for them to handle the dispatch through customs. I fill it in and send it back immediately.
• Day 9. DHL emails me to say they are "going to initiate the corresponding procedures for customs dispatch". Estimated delivery date comes and goes.
• Days 10 and 11. A weekend. All quiet on the Western Front.
• Day 12. I receive my daily status update email, informing me that my parcel’s currently in an "exception state".
• Day 13. Another daily status update ("exception"), and the status page again tells me that DHL needs some information from me and will contact me to let me know what they need; given that they don’t contact me, I contact them, asking them what they need.
• Day 14. I receive a reply from DHL, indicating that they are still waiting to physically receive the package (which seems false, given all the status updates showing the package’s transit — in DHL’s custody — from the source country to the destination country), and that I should write to the seller to ask them what date they sent it. Finally, later in the day I receive email from DHL inviting me to pay the import duties on the order, which amount to 32.6% of the cost of the goods. Why is this amount more than the expected 21% (this is the rate of the Value Added Tax in my country)? Well, it’s because DHL helps itself to 52.51€ for its "administration" services, in addition to the 9.99€ I paid for shipping in my original order (supposedly, to cover delivery in the span of "3–6 business days"). Mousing over to see the description of what these "administrative services" consist of, I am greeted with the dystopianly inaccurate claim that they refer to "assitance provided by DHL Express to facilitate the efficient clearance of shipments through customs processes; this includes documentation management, ensuring regulatory compliance, and handling duties and taxes" (emphasis added).
• Day 15. Item is actually delivered.

So, in that 15-day itinerary, 9 days were spent with the package sitting on some shelf waiting to be "processed", while I received an irritating bombardment of inaccurate notifications and requests to engage in hoop-jumping. That they would charge me a premium to facilitate this circus, and have the gall to describe it as "efficient", is the most annoying part.

Seeing as I hang out on Hacker News, I’ve been aware of Advent of Code for many years now, but it was only in 2023 that I participated for the first time.

In 2023, I fully completed 16 days (both parts)^[1] and partially completed an additional 4 days (only the first part). There was one day that I attempted but didn’t even solve the first part, and 4 days in which I didn’t participate at all. I optimized for getting the solutions quickly, not necessarily elegantly, and if I felt like I was taking "too much" time on a particular problem, I stopped.

In 2024, I completed all 25 days, and the whole business felt subjectively easier. I wasn’t sure though: was it really easier than the year before, or had I just gotten a bit better at solving this kind of question? Alternatively, had I tried a bit harder in 2024?^[2] Might it even be true that I was, um, "scrappier" in 2024; that is, more willing to throw elegance, purity, and truth out the window in service of getting the right answer?

Ideally, I want my solutions to be based on applying my toolkit of data structures and algorithms to the problem at hand. I think it’s ok to look up details of a specific algorithm that you know about but which you can’t necessarily implement from memory alone, but not to go onto Reddit in order to have a recipe for how to solve the problem handed to you on a platter. This year, for example, I used Dijkstra’s algorithm a couple of times (day 16 and day 18); this is a path-finding algorithm that is simple enough that I can mostly remember the shape of it even if I only make use of it once a year, but my first cut wasn’t quite right and I needed to check the details. On day 23, I used the Bron-Kerbosch algorithm for finding the maximum clique in a graph; that was a case where I knew the kind of algorithm I wanted, but couldn’t recall the name of it, so I went to Wikipedia and skimmed through the list of Graph algorithms to find what I was looking for. Given that I couldn’t remember the name, I definitely wouldn’t have been able to implement the algorithm without looking it up. That seems like fair game to me.

Likewise, for non-trivial data structures (ie. anything that doesn’t come with the language or standard library), I think it’s ok to copy an implementation I’ve previously written. This year, the only such thing I grabbed was a binary heap implementation and the corresponding thin wrapper around it that turns it into a priority queue. At one point, I thought I might use a Union-Find but I ended up not doing so. I wouldn’t get very far writing a Union-Find implementation from scratch without looking it up. And I think I could write more than 50% of a heap implementation without looking anything up, but it would probably have bugs, and I’d have to look up the rest anyway, so I figure I may as well use an at least somewhat battle-tested implementation that I myself have previously produced.

Needless to say, no LLMs for something like Advent of Code. Using them seems not to be in the spirit of the exercise.

So, I’ve got principles, if you know what I’m saying. But there were a couple of days this time that troubled me, where I used "by-hand" analysis of the problem input, or what I’d call "extrinsic knowledge" to strongly guide the solution, as opposed to coming at things from "first principles":

• On day 17, I figured out what the provided byte-code was supposed to do (ie. I effectively "disassembled" the byte-code and wrote down exactly how the information would flow through the registers), and used that knowledge to run a search over possible values, effectively running the computation in reverse, ultimately arriving back at the necessary initial value. In other words, I didn’t write an algorithm that would run over the input data and spit out an answer; instead, I wrote code that would leverage some analysis (that I could have done with pencil and paper) to spit out an answer.

• On day 24, I used knowledge of how binary addition can be implemented using logic gates to explore the problem input finding deviations from the expected wiring. That is to say, instead of taking the problem input and asking "how can I make use of data structures and algorithms to solve this task?", I asked "how can I make use of data structures and algorithms, combined with knowledge of how logic gates can be used to perform addition^[3], to solve this task".

Both of these felt somehow like "cheating", but the truth is I cared more about getting the answer than doing it in a "pure" way, so I went with it. Based on comments from folks at work, I feel like at least a few of my colleagues were able to produce more "fundamental" solutions for both of these days.

In any case, let’s get back to our initial question. Was Advent of Code 2024 easier than 2023? That’s a very hard question to reliably answer, so I posted an ultra-scientific poll at work and found that 9 respondents thought 2024 was easier, and 1 thought it was about the same. I guess that settles it, then.

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1. On one of those days, I got stuck, and ended up looking on Reddit for a hint for how to proceed with the second part. ↩︎

2. I don’t think so, as I there were only a few days where I felt like I took longer than I should have to arrive at a solution. For the most part I felt like I got things done more quickly than the previous year. ↩︎

3. Knowledge that I vaguely recalled, but which I obviously had to look up online to actually get the details right. ↩︎

Let’s talk about the big three:

• Free will
• Self
• Identity

Free will

Endless flows of ink have been spilled debating the nature of free will, and given that I only hold half a PhD^[1] (not even one in philosophy) I don’t think I’m qualified to do justice to them all^[2]. Nevertheless, for the purposes of context, I’m obliged to at least delineate what I see as the three main camps:

• Libertarian free will: The belief that free will — the capacity to make choices — exists, is real, and is not an illusion. This is the natural view that we all start with, because as we grow up, it certainly feels like we’re making choices.
• Determinism: The position that all future events rely on chains of causation, and that this precludes the existence of actual free will (at best, the illusion of free will is permitted).
• Compatibilism: A series of gymnastic somersaults that philosophers perform to make the claim that true, non-illusory free will totally can exist within a deterministic universe. I won’t bother describing it further because it all strikes me as definitional sleight of hand and not much more than smug cleverness for cleverness’ sake.

In practice, if you’re religious, you probably subscribe to libertarian free will. Without this kind of free will, all this business about choosing to believe doesn’t really make sense (and the idea of burning in hell for not believing in God seems a wee bit unfair, if you don’t have any choice in the matter). Other beliefs adjacent to or overlapping with religion — things that might be labelled spiritual, or mystical, or supernatural — are also likely to lead you to choose this version of free will; if you believe in something like a soul with an existence that is independent of the physical substrate of our bodies, if you believe in reincarnation or out-of-body experiences, for example. Even if none of the above apply, it’s still possible that you might have a view of selfhood rooted in your subjective experience which leads you to feel like there is something inside you that is actually making decisions.

Atheists, scientific types, and such, are more likely to believe that determinism rules out real free will as a possibility. When two particles in a system collide, the laws of physics tell us what happens next. Your body and your brain are made of lots of these particles. Given enough knowledge about the configuration of all those particles at any given point in time, these laws should tell us what the configuration will do as it evolves over time. In this view, the appearance of free will is just an emergent phenomenon that arises from the low-level details of the system playing out. At the macroscopic, subjective level, we perceive our decisions as being products of "free" will, but the argument is that they’re all really determined.

The ironic thing is that an utterly pre-scientific Buddhist monk wandering over a thousand years ago through what is today India could have and would have arrived at the same conclusion without any discussion of particles or the laws of physics either, but rather through quiet observation and meditation. The same subjective awareness that some would use to claim that free will is real, can be turned inwards and lead to the complete opposite conclusion. People who meditate often recount how they become aware that things like decisions — and not just decisions but also ideas, words, feelings, and more — appear to arise as if from nowhere, with no sense of internal authorship or ownership.

I personally hadn’t thought much about all of this until about 15 years ago. When I did start to think about it, coincident with dabbling in meditation, I found through the combination of the simple logical argument for determinism with the support of observations I could make in my (inexpert!) mediation sessions, it was pretty darn obvious that free will was indeed an illusion. If you don’t already believe this, I’m not going to try and convince you here because I know there is an ample quantity of well-crafted and convincing argumentation online.

We humans are basically machines, complicated organic "computers" that run algorithms more or less deterministically^[3], and when we agonize over a choice and eventually arrive at a determination, the decision that pops into our mind is no different from a punch card popping out of a computer at the end of a computation. When I make the choice whether to eat junk food or a healthy snack, I might feel like I’m weighing it up in my mind, but really all that’s happening is my hardware is carrying out its programming and arriving at its inevitable result. And moment to moment, when I’m selecting what word to say next in this sentence, I can’t really claim any real agency in the process; the words are very much just arriving from "somewhere", the output of layers of calculation that I can only begin to fathom. There is no more a "me" inside my head wielding the quill and ink than there is a "self" inside an LLM deciding what the next token should be.

There are some smart fellows out there, like Roger Penrose^[4], who try to square all this in such a way as to make determinism compatible with free will. They do this not in the way that philosopher compatibilists do (eg. by doing things like redefining free will as nothing more than "the subjective experience of making decisions", and claiming that somehow means they can claim that free will is real — ie. not an illusion — after all, while remaining totally compatible with determinism). Instead, they make the argument that conciousness only exists because of quantum processes inside the brain — and not because of processes happening at the cellular level — and that within their framework, true free will somehow emerges due to (hand-waving) something about quantum state. All this stuff is beyond me, but I will say that it doesn’t appear to pass the "sniff" test; it may be that Penrose is right and everybody else is wrong, but the more likely case is that the widespread skepticism of this particular idea among his peers is probably well founded.

Believing that free will is an illusion doesn’t relieve you of your obligation to respect the laws of society (that is, you can’t go off on a rampage of theft and murder and then make the claim that none of it was your own doing). I think that one of the reasons society at large works, and also why local relations between individuals "work", is because we’re mostly all operating under the tacit agreement that free will does exist. Or put another way, that even though it is an illusion, it behooves us all to behave as though it weren’t^[5].

Self

I said that free will isn’t the only problem though. When you allow the domino of free will to fall, the next one to topple is usually that of "the self". The same kind of meditative practice that can lead you to conclude that free will is an illusion can in turn take you to a place where you realize that the self is an illusion as well.

It does feel like a bigger leap to make, because the sense of selfhood that we all subjectively experience accompanies us much more intensely, continuously, and pervasively than that of free will. Most of the decisions we make in our life are so low-key — like where to place our next foot-step when walking down the street —that they barely rise above the threshold of our awareness. But the experience of self-hood frames and constitutes almost everything we do.

There is an almost ineludible sense that there is a "you-ness" located somewhere inside you, most usually inside your head, looking out into the world through the windows of your eyes. This sensation is so normal and so continuous that we rarely speak of it, taking it for granted, and we instead name other states — like "flow states" — for those much rarer moments when you somehow lose your sense of self; like when you get absorbed in a good book, or lost in a task that captivates your attention and makes you lose track of time.

But if you think that a human being is a deterministic machine chugging along according to the rule of physics, it’s hard to explain how consciousness arises within that machine, and once it does arise, how and when it crosses the threshold of self-awareness^[6]. Clearly, it does cross that threshold, but doing doing so doesn’t necessarily give us a handle on what the self is.

If you could simulate your connectome and all the interconnected biological hardware on a computer, could such a thing be said to be conscious? If you believe in substrate independence — and doing so is a small step to take once you’ve accepted determinism — then it seems inevitable that a simulation must be said to be capable of consciousness. In this view, defining what consciousness is might boil down to something reminiscent of the Turing test: conciousness is that property that entities appearing to exhibit consciousness possess; a tautological and insufficient definition if ever there was one^[7], but fortunately, not one I have to defend to a thesis committee.

Once again, we don’t have to seek scientific explanations here if we want to arrive at this particular destination. Meditation alone is enough to convince us that what we know as the self is an illusion. I am far from an expert practitioner (and in fact, it’s been many years since I meditated regularly and in a structured, routine way), but even my inexpert dabbling was enough to provide me with access to a range of observations that revealed how contingent, arbitrary, and fragile the fabric of subjective experience is. Thoughts, emotions, sensations, arise as if from nowhere. The brain is very practiced at sense-making and arranging these into a semblance of order, a linear narrative^[8], but when you stop and observe what the experience of experiencing is really like, in detail, it becomes clear that what is going on is a lot more happening and not quite as much being as you perhaps thought originally. That’s a pretty vague thing to say, but here once again I’m going to make use of my grand excuse that there are many others out there who have described all of this far better than I can, and their work is easily accessible for those who are interested.

We’re so darn good at making narratives of things, that I think our very experience of the passage of time is mostly a construction that masks the reality of what’s really happening in our neural machinery. Our subjective experience feels linear and sequential; even if our minds appear to jump rapidly from one thought to another, we only ever seem to be thinking one thought at a time, just as we can only really look at or attend to one thing at a time (even though our eyes might be darting all over the place). In reality, I think our mental apparatus is massively parallel, and it’s only at some very high level where our consciousness resides that we impose a single-threaded integration of all of those parallel processes running underneath^[9].

So, the self is an illusion, yes, but a very useful one, as I will describe in the next section.

Identity

Maybe it’s a mistake to try and draw a line between "self" (which I’m using above to refer to the construct that we maintain in our moment-to-moment experience) and "identity", but I’m going to try.

The self may be an illusion, but the concept of a real stable identity is an obviously necessary and useful conceit. Your conciousness may be an emergent phenomenon relying on the operation of an incredibly complex biological machine, but as part of society it is evidently very handy that we assign ourselves names, addresses, driving license numbers, and so on.

The bank probably doesn’t care if you believe in free will, or even if you’ve mediated so much that you’ve started to question the boundary between your own organism and the broader world in which is it is embedded^[10], but it sure as hell wants to know where you live and a bunch of other "metadata" about you before it will loan you the money to buy a house. And in your relationship with your family, your friends, your employer, and the people you interact with in your neighborhood, it is anywhere from "handy" to "essential" that you present a stable identity to the world that is sustained over time.

If you’ve gotten this far, it will come as no surprise to you to learn that I think this kind of thing is an illusion of sorts too. I’m not even referring to the fact that most of the cells in our body gradually turn over^[11], turning us into living, breathing Ships of Theseus.

I’m also not referring to the fact that the "you" you see in the mirror slowly ages and changes, such that you can look at photos of yourself from 10 years before and marvel at how different you look.

Rather, I’m talking about how susceptible to change your internal model of yourself is. Part of that is related to memory and forgetting, which seems to affect us all as we age, even those of us who never fall prey to actual dementia. I think the Inside Out movies do a great job of fictionalizing aspects of something that we’ve all experienced: the role of "core memories" and "core beliefs" in sustaining and defining a personality (and how these can be eroded or replaced over time); how things get shunted into long term memory; how things get forgotten or lost forever.

Conclusion

I want to say that the big three topics that I’ve addressed in this blog post arrived one-by-one in my life, and in the order that I’ve discussed here. But, I don’t know if I can trust my memory about that.

You see, one thing I’ve had a growing awareness of is that my memory is changing as time goes by. Old friends sometimes recount episodes of things we did together that I have literally no recollection of although they do sound like things that I might have done. In general, my impression is that among my friends I am probably the one who remembers the least. And this was a bit surprising to me, because I had always prided myself on my nearly photographic memory^[12] back in my university days, which had seemed to me at the time like a totally unfair advantage.

I don’t think this is all about aging, although some of it might be. As an avid computer user, an early internet adopter, and assiduous archiver and note-taker, I have observed in myself a tendency to remember less and less as time goes by, instead developing skills and practices that enable me to find information again when I need it. That always struck me as a learned adaptation to my environment as opposed to a change in the functionality of my memory. But there has also been a sense of "overflowing", that my brain somehow filled up long ago and no longer makes much of an effort to retain new information. Nowadays when I see movies, it’s common for me to forget basic elements of the plot only weeks after seeing them. When I was younger I could give detailed recounts of entire scripts, but now I basically just remember whether I liked the movie or not.

It’s reflecting on memories that prompted me to finally finish this blog post. I created this file, blog/free-will.md over two years ago with the intent of saying something about it, but never made a start until a couple of days ago. The thing that pushed me to actually do it was an experience last week wherein I was trying to account to somebody why it is that it is so hard for me to focus on myself, and why I love "flow" states so much, because they allow me to completely lose myself in something "other"^[13].

The first order explanation is that I find those states subjectively pleasant, but the second order one is that I like losing myself because I don’t necessarily have a very strong sense of identity. And when I dig deeper trying to understand why that might be, I have to admit that I’m skeptical of the reliability of my own memories^[14], and I’ve spent a lifetime pursuing distractions that took over me and had me thinking about anything but myself.

There are contradictions and ambiguities to unknot here — like why I would spend so much time analyzing my own operation, why I would feel so "motivated" to do so even when I quite clearly don’t believe in free will to do anything at all — but the nice thing about a belief in determinism is that I don’t have to feel bad about shrugging my shoulders and ending abruptly. After all, it couldn’t have been any other way…

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1. Quite possibly the most useless non-qualification of all. ↩︎

2. The Wikipedia page on Free will makes a good start though. ↩︎

3. When I say "more or less" here I’m not questioning that determinism is real at the level of the laws of physics. When you zoom in to the quantum level, there are certainly stochastic processes that we can’t predict the outcomes of (eg. we don’t know what the result of a measurement is going to be, although we can assign probabilities to different outcomes), but the laws themselves — like, evolving a wave function according to the Schrödinger equation — robustly define what happens to the system given a set of initial conditions. The "more or less" I was actually intending here was a reference to the unreliability of these human machines: cells degrade, DNA gets mutated, we age, and if our lives can be a thought of as a quadrillions of computational steps carried out by a machine comprised of trillions of cells, it’s to be expected that some of the operations are not performed exactly as expected. Nevertheless, such imperfections mean nothing for the status of our will, free or otherwise. ↩︎

4. Winner of the Nobel prize in Physics in 2020 for his work on black hole formation. ↩︎

5. An analogy I like to draw here is with the Efficient Market Hypothesis. I don’t think that markets really are efficient, but the most useful (and therefore rational) thing for most of us to do is to behave as though they were. ↩︎

6. So many fun rabbit holes to go down here, leading to interesting (but in my opinion implausible) places like panpsychism and such. ↩︎

7. Perhaps something only a compatibilist could accept. ↩︎

8. We do this at a very high level when we tell stories about the world, or create symbolic edifices that seek to explain and illustrate truths about reality, but we also do this automatically on a moment-to-moment basis as we integrate sensorial data and just go about our business of existing. ↩︎

9. This is how I explain one of my favorite surreal experiences, that of the "premonition". I routinely feel like I know what song is about to come on next in shuffle play, and when it does, I get the strong impression that I somehow started hearing it before I actually heard it. I don’t think this means I have the ability to see (hear) the future, though. Rather, I think the part of my brain that’s responsible for integrating sensory data and for presenting a linear thread to my subjective experience is having some kind of hiccup, and it ends up presenting events out of order (imagining that I had a premonition, when I really just heard the next song popping out of the shuffled playlist). ↩︎

10. Unless, perhaps, the mediation interferes with your ability to hold down a job. ↩︎

11. I’m no biologist, but my understanding is that some cells turn over very rapidly indeed — with the skin, hair, and liver tissue being among the fastest, on the order of weeks — while others are much slower or don’t turn over at all (neurons, for example). ↩︎

12. I say "nearly photographic" because I didn’t seem to have a universal ability to recall what I had seen, but rather I had a specialized version of this where I could rapidly find again something I had read in the past because I had a spatial recollection of where the words I was looking for had appeared (both in terms of how far into the book, but also where on the page I was to find them). ↩︎

13. And the reason I was having that conversation was because I’d had a weird experience a night or two before, when I’d been lying in bed around dawn and for no apparent reasons had suddenly remembered something I hadn’t thought about for over a decade and had in a sense "forgotten" (although evidently not completely), and which in turn made me question one of the "core beliefs" that I had come to hold about myself. ↩︎

14. I’m not talking here about confabulation or hallucination or anything like that, but simply a kind of gradual amnesia that slowly sets in over time, leaving larger and larger lakes of darkness. ↩︎