Why did the chicken cross the road?
Chickenjoke.com has every conceivable answer to that enduring question.
Tuesday, May 31, 2005
Sunday, May 29, 2005
This who have been reading this site may have deduce a particular fact about the author of the site:
- The author is an unabashed geek
- The author is fascinated by religion
One thing that people instantly assume upon discovering my atheism is that I must, by definition, have an inherant hostility towards religion. To be sure, there are a number of things about religion that I can't agree with (most particularly the theistic conjecture that is central to a majority of religious beliefs) and there is a lot that I find objectionable in particular religions. Never the less, I actually do not have an inherit hositility towards religion, on the whole, and, in fact, consider it a valuable (if distorted) mirror of the human psyche.
Given this, my choice for this week's off-site essay nicely combines my geekiness as well as my fascination with religious subjects. It's a sermon by a Unitarian Universalist preacher. The topic of the sermon is The Lord of the Rings.
The semon is in PDF format so you will need to have Adobe Acrobat Reader installed to read it.
Thursday, May 26, 2005
If I could strip myself
Of these fearful concerns,
Discarding them into
An unused corner
To be laundered
At some later day,
I would run naked
Through the high grass of my dreams,
With wishful winds against my face,
My skin prickling with possibility,
Luxuriating in the blue freedom
Of an unbounded sky,
But the zippers snarl,
The clasps do not unbuckle,
And I find that I cannot
Simply shrug this straighjacket
From my shoulders.
Tuesday, May 24, 2005
For this week's fun, I offer you the most absolutely disturbing educational flash animation that I've ever seen. Sample text:
"This is Mr. Split Brainy wondering what the brain smells like. He doesn't think it smells like anything in particular."
Sunday, May 22, 2005
In the prior installments of this essay I introduced the concepts of teleology and etiology and their relationship with science. In the last essay, I advanced the proposition that science can approach some teleological questions and proposed that the phenomenon of play was one such area. I finished by conducting a partial survey of life forms, eliminating the vast majority of organisms from consideration. At the end of the installment, I had limited the scope of inquiry to mammals and offered the reader the challenge to see if they could determine the unifying factor that links those mammals which do play.
I suggested that you might want to start with a random sample of mammals. So you might have come up with a list something like aardvarks, bats, cats, elephant, horse, mice, mole, sloths, etc. You might then have divided them into animals that are known to engage in play (cats, elephants, horses), animals that don't (aardvarks, bats, moles, sloths), and animals that you might not have been sure about (say, mice).
On any comprehensive list there are going to be questionable cases. We must first decide whether or not we can, in fact, categorize such outliers. In my list, I put mice in the questionable column. The reason that I did so is that mice in captivity often do seem to engage in play like activity. I know one girl who had a group of mice that would all get on their spinning wheel, run it up to a high speed, and then grab on to the wheel's frame which caused them to get spun around on the inside of the wheel (which, if nothing else, proves that mice don't suffer from motion sickness). That certainly seemed like play; however, a wheel in a cage is not a natural environment. It is well established that many creatures will exhibit anomalous behavior when put into unnatural circumstances. Do mice in the wild exhibit playful behavior? I haven't been able to find evidence that they do. So, which column should mice fall into?
There are any number of inaccurate stereotypes concerning the workings of science and not all of them come from the detractors of science. Many people who are "pro-science" have a notion that scientists will scrupulously include all experimental data in their considerations. In principle, it is true that data shouldn't be discarded on the basis that it contradicts a given hypothesis, but this isn't quite the same as saying that all data is automatically going to be included. This isn't always so.
Let us suppose that I'm conducting experiments on the effects of various salts on the boiling point of water. I set up a traditional experiment where I have a control (several beakers of distilled water) and an experimental set. I conduct a series of measurements for salt X and find that in nineteen trials the boiling point clusters closely around 102.7 degrees centigrade. In the twentieth run, however, my thermometer reports a boiling point of 131 degrees!
If we were to follow the stereotype, I would dutifully record the data point on my carts and adjust my curve to fit it in. In practice, though, I know damned well that 131C is not a real boiling point. Perhaps my instruments have a defect, or maybe there was a patch of superheated steam that threw of the thermometer. Whatever the case, I know to a high degree of certainty that the measurement is meaningless. I can do one of two things at this point. I can either exclude it from my data entirely or include it in the data and discount it from the conclusions.
Modern practice favors the latter. Modern science is a very competitive venture and anything that could even potentially look like data manipulation can be used to destroy one's career; however, whether or not I plot the data in my submission, it would be equally irresponsible for me to allow it to impact my results and doing so would also get me into hot water (if you'll pardon the pun). Given this, I'll note the outlier but I will specifically say that it is an outlier and that it isn't included in the calculations for the actual data curve. It should be noted that many respected experimentalists from the earlier days, when science was more of a gentleman's hobby, didn't bother to do that much. Bad data was tossed out on its ear without any hesitation.
So, having dispensed with the outliers, for the time being, let us look at the data and offer some tentative hypotheses.
You may have noticed that there seem to be a lot of carnivorous animals on the list: wolves, lions, hyenas, and so forth. Could it be that being hunted is the factor that we are looking for? But what about elephants and horses, who are both herbivores, as well as primates, which span the gamut from strict vegetarians (gorillas) to predatory omnivores (such as chimps and, yes, humans).
Clearly there is more to the matter than diet, however, before we more along too hastily, we should note there are, in fact, a lot of carnivorous predators and periodically predatory omnivores. Should we, perhaps, consider the herbivores on the list to be outliers? In this case, I think not. There are enough herbivorous creatures that we can't simply dismiss them from consideration without running the risk of skewing our answer. What we need to do is to think about what commonalities there exist between the predators and the non-predators on our list. We should, however, consider the predatory bias to be a clue.
My goal, here, is to give you an idea of how scientific inquiry works. The fundamental point that I want to convey is that science is systematic. Too many people have an image of science where a scientist takes a look at some new phenomenon, ponders it briefly and then, from the vastness of his intellect, produces just the right insight to explain it. As much as so-called eureka moments are celebrated, real science is a grueling and often tedious exercise where observation after observation is tested against one tentative hypothesis after another. Even the grant theorists such as Einstein had to consider mountains of prior observation and theory before producing their own. The public, too often, sees science as a sequence of facts that are provided on demand. They don't see the working process that is responsible for the production of those conclusions.
For the purposes of this essay, I'm providing an abbreviated account of the considerations that we should be examining. If this were a real scientific investigation, we should be considering dozens, if not hundreds, of alternatives and we should be using more than a random sampling of mammals as our dataset. Fortunately for us, I'm following a trail that has already been laid out by the real workers. Because they have put themselves to the effort of being systematic, I can afford a certain degree of laziness.
I would like you to take a final moment to consider the data, however, before moving on. Consider what we have and ask yourself what commonality binds play.
As it happens, there are actually two factors that are almost universally present in animals that play. The first factor is that animals that play are not born with a full set of mature behaviors. The second factor is that the behaviors that they engage in while playing resemble behaviors that adult animals employ in non-play activities.
Let us consider a wildebeest calf, a lion cub, an elephant calf, and a human baby. The first does not engage in play while the latter three do.
When a wildebeest is born, the very first thing that it needs to do is to stand up. The reasons for this are very good: a calf that cannot stand on its own four legs is in serious danger of being eaten by passing carnivores. One of the most horrific videos that I've ever seen was a mother wildebeest with a half born calf being torn to shreds by hyenas. Clearly, time is of the essence.
A lion cub, by contrast, has a strung resemblance to a domestic kitten. It is born blind and feeble. Likewise, so is a human baby. An elephant calf is somewhere in the middle. Elephants are very protective of their young, and they have the bulk to back up their protectiveness, so an elephant calf isn't at high risk of being eaten by the local fauna. On the other hand, elephants require a large foraging area and have to move fairly large distances to eat. Elephants, unlike lions, can't create a crèche for their offspring, and they can't carry them from place to place, as humans can do, so a baby elephant needs to get her feet under herself fairly soon.
This represents something that we might call developmental luxury. A wildebeest does not have the luxury of being born unable to walk, nor does an elephant, but a human and a lion don't have to be born with those capabilities. We have, so to speak, the luxury to take our time to develop those capabilities. This is a very big clue, by the by.
Let us return to our wildebeest. Our wildebeest is not only born knowing how to walk. She also knows how to forage, how to spot predators, and how to stay with her herd. She also has a set of behaviors that cause her to remain close to her mother and which prompts her to nurse on a periodic basis (as do lions, humans and elephants). As she matures, she will lose these while gaining certain sexual behaviors (again, as will lions, humans and elephants). This, for the most part, represents the whole of her knowledge set. Wildebeests don't need to know a lot in order to be successful. A wildebeests life may be occasionally stressful (you try being on someone's lunch menu) but it is not a complicated life.
Our lion cub, on the other hand, is going to need to know how to hunt, which means not only knowing how to chase down animals but also how to select favorable targets and how to coordinate their kills with the other members of their pack. There is also a range of non-hunting behaviors that lions need to develop which also relate to their pack structure. A lion needs to be able to discern its place in the pack hierarchy and to know how to behave with respect to other members in the pack.
Elephants, obviously, do not hunt and there's not much that they need to know about foraging (plants are docile prey). This is not to say that an elephants mental space is small. We humans have an expression, "as plain as the nose on your face", which means that something is obvious and simple. If elephants had language, that expression would be an oxymoron. Baby elephants are not born with well coordinated trunks (just as human babies don't have well coordinated limbs and fingers). They can get away with this because they are highly social creatures and their mothers can help them along until they get their trunks under their full control. Elephants also have a fairly complex social structure which they need to integrate with.
Humans, of course, are the most complex case. A human child is born without control of her body, knowledge of her society, any skills, or even language. By the time she becomes an adult, she must acquire all of these things.
Let us call this feature developmental complexity. Although our three examples have the luxury to be born with less than a full compliment of behaviors, they also have the obligation of developing a behavioral set that is substantially more complex than their wildebeest peer.
Before we continue, I want to head off a potential red herring. Elephants, humans, and lions are social creatures. You may be tempted to suppose that this is the critical ingredient; however, many playful creatures are solitary. Most species of cat, for instance (including domestic cats and tigers) are non-social. Socialization isn't irrelevant but, like carnivorousness, it isn't the whole shebang.
Returning to the topic, you may have noticed that there is a word that I haven't been using. That word is "learning". I've been avoiding it because it is the final clue. Animals that play are animals that are born knowing less than they know about the world (developmental luxury) and which have a lot that they will ultimately need to know about the world (developmental complexity).
Play behavior is synonymous with learning behavior. Juvenal animals play in order to learn how to be adult animals.
At this point you might suppose that we have our teleological answer. We are not quite there, yet, unfortunately. We have one more question that we need to address: why do some animals need to learn anything in the first place? In other words, what's the advantage of learning?
I will leave this for you to ponder this until the next installment. I will give you a clue though: I'm deliberately asking the wrong question, but for the right reason.
Friday, May 20, 2005
Thursday, May 19, 2005
It is late
And the weather is Decembered.
Yes, that's not really a word,
But bear with me.
In a place with a warmth and a love,
And it's small but we call it home,
And I'm wondering how easy it would be
To fall out into that Decembered weather,
And so I'm typing out a distillation of
My skills, these little talents I have,
(And maybe a white lie or two for seasoning)
Trying to say,
Choose me! Pick me! Take me!
Me! Me! Me!
With as much dignity as a pup
Nosed-pressed to a pet store window
And I imagine you,
Reading this summation of my self:
Who is he that we need him?
Who is he to be trusted
With our time, money, and responsibilities?
And there are other hims and hers out there
Tugging at your sleeve,
Begging for your blessing
And they all have warm little homes
That they love, too,
And I hate them, wish they'd go away
Because they are a distraction
That tries to steal your eyes away
From me, me, oh please this time me!
All I can do is give you this
Here-I-am sheet of paper
Hoping that it will suffice to tell you
That I am the one you want.
Tuesday, May 17, 2005
Long, long before The Daily Show there was Not Necessarily the News, which was a kind of sketch comedy take on the news. Overall, it was a medium funny show but it did have one segment which achieved a popularity all its own: I speak of sniglets.
A sniglet is defined as a word that is not in the dictionary but which ought to be. Viewers would send in their suggestions and host Rich Hall would read the best entries on the air. My personal favorite is flopcorn, defined as "The unpopped kernels at the bottom of the cooker".
Bert Christensen's Truth & Humour Collection has a nicely representative sample of sniglets. Enjoy.
Monday, May 16, 2005
" A new survey to be released Monday reveals a wide gap on many media issues between a group of journalists and the general public. In one finding, 43% of the public say they believe the press has too much freedom, while only 3% of journalists agree. Just 14% of the public can name “freedom of the press” as a guarantee in the First Amendment to the U.S. Constitution, in the major poll conducted by the University of Connecticut Department of Public Policy."One of the essential paradoxes of a democracy is that the citizens of a democracy can freely choose to dismantle it. We haven't quite reached that point in America. The majority still accept the necessity of a free press and, beyond that, the courts have remained consistent in their defense of the press.
Be that as it may, when I see that such a large number of people are willing (and, perhaps, eager) to allow the government to curtail the press, I wonder. My concern is multiplied by the realization that prominent members of the legislative majority have been making calls to restrain the judiciary.
I believe that this is a perilous time. Fear has always been poisonous to democracy. FDR was not speaking hyperbolically when he said that the only thing we have to fear it fear itself. Since 9/11, we have been existing in a state of fear. We have an executive branch that has been actively capitalizing on that fear to advance its own ends. It is during such times as this that people are most willing to compromise their freedoms for the sake of perceived necessities. It is precisely at these times that we must be most strenuous in resisting these urges for comfort and safety at the expense of our precious freedoms. I fear the fearfulness of the people.
I would urge my American readers to stand up and speak out. When you hear coworkers, friends, neighbors and family suggesting that we should be willing to give up a little freedom in order to achieve a sense of comfort, do not be silent. Remind them that our freedom has been bought at a very steep price and that it dishonors those who died to grant us our rights if we cast those treasures aside so easily and timidly at the first hint of danger. Even more importantly, write to your representatives. Do not email them, write them and tell them, in your own words that you are not willing to sit idle while our Constitutional guarantees are eroded. Insist that they do their jobs as the stewards of our democracy.
Democracies can die suddenly or they can die the death of a thousand cuts. Let us keep ours from either fate.
Sunday, May 15, 2005
Sorry guys, I know that you were expecting the third installment of my essay on science and teleology. Unfortunately, I've been so busy working on a presentation for work that I haven't had the time to complete it.
Please accept my apologies and my assurances that I'll have it ready by next week.
Thursday, May 12, 2005
I speak in tongues,
None of them my own.
A Babylonian gabble of demons
Have infested my mouth,
Leering between my teeth
When I try to smile.
I cast a hard rage at them
And try to spit them to the ground.
Mothers move to shield their children
From the madman in their midst.
I try to reason with them
But they skewer my arguments
On pitchforks and pikes,
Stuffing them back in my throat
So that I may choke on their taste.
I know that no one can hear me
Because my voice is lost
In a wilderness of words.
So I sit.
So I sleep.
So I wander the streets
With wide eyes and fear,
Speaking in tongues.
Monday, May 09, 2005
I wasn't expecting to like Napoleon Dynamite (largely because of an utterly incomprehensible media campaign by MTV). I finally saw it on DVD because a friend of my girlfriend strongly recommended it. Much to my surprise, I really liked it. It is, indeed, a true example of geek cinema.
If you liked it as well, you may like today's link to the Napoleon Dynamite Soundboard, which is a clever little Flash tool with various quotes from the movie.
Sunday, May 08, 2005
I have not, on the whole, been a been fan of Wicca.
This is not because I disagree with its ontology, per say... I believe that Wicca is no more or less valid than any other religion out there (and if that sounds coy, I remind you that I'm an atheist &mdash do the math), nor is it because I have any moral objection to Wicca. I am certainly not concerned with the whole "witchcraft" angle, nor am I particularly concerned with the fact that Wicca has a rather dubious historical basis (again, something that I don't think distinguishes it from the majority of other religions in the world).
The biggest issue I have with Wicca has been the Wiccans. To be specific, I find that a lot of Wiccans strike me as being religious dilettantes. While I find nothing wrong with Wicca's core ideologies (other than the fact that they are a bit hard to pin down), I find that a lot of Wiccans seem to have joined the religion for the simple reason that Wicca has a very flexible belief structure. That alone isn't necessarily a bad thing. Buddhism, which I rather do admire, also has a fairly flexible range of potential beliefs that a given adherent can accept; however, where I find that most Buddhists approach that flexibility seriously and consider it an imperative to conscientiously work out their philosophy of the world, I find that many Wiccans seem to treat their religions flexibility as a lax fill-in-the-blanks theology that they can tailor to their personal convenience.
Fortunately, there are exceptions. I do respect those Wiccans that really take the time to think through their moral and philosophical stances. I am disappointed that they seem to be the exception.
Today's link is from the Existential Harmonics site which is run by one Kyle Lewis, who is also a friend of mine in real life. Kyle is definitely an extraordinary Wiccan and an extraordinary person. Recently he took the time to write down his personal values, framed by his Wiccan theology (as well as his studies of Kabbalah), in a systematic set of essays. He hasn't quite finished (ultimately he's going to have 10 + 1 categories); however, what he's done so far deserves reading. The link is to his introduction which he's thoughtfully cross-linked with the individual essays (currently through essay nine).
If you want to see a well developed set of moral considerations from a religious perspective that most people would find alien, exotic and, perhaps, threatening, I would implore you to take a look at what he's written.
Thursday, May 05, 2005
Tuesday, May 03, 2005
This week I thought that I'd go retro. Very, very retro. Long before computers and calculators, many people used abacuses (or abaci if you're fond of pretense) to perform complex calculations.
I've often played with abacuses (for some reason, a lot of dentists that I've gone to have had them in their waiting rooms) but I've never really understood how one is supposed to use them.
If, like me, you've been curious about this, the Abacus: The Art of Calculating Beads site will not only teach you how to use an abacus but it also provides an excellent history of the abacus as well as links to various abacus related sites, including a great Feynman anecdote and a truly nifty Java applet of an abacus.
Sunday, May 01, 2005
In the previous installment of this essay I discussed the distinction between teleology and etiology, with teleology being the search for purposeful explanations and etiology being the search for causal explanations. I noted that one of criticisms of science is that it can not be used to find teleological explanations of phenomena and that it is limited to the realm of the etiological. I explored the question and offered some examples of questions that science, indeed, would not been well-suited to find teleological answers. I closed, however, by claiming that there were some questions that science could provide such an example for and that I had such an example… which I deferred from providing.
The example I had in mind is the phenomenon of play.
I could, at this point, try to give a technical definition of the word. Since this is Unstructured Musings, however, rather taking the risk of being sidetracking by a tricky definition, I'm going to take a shortcut and say that it's what you intuitively suppose that I'm talking about. Think of children playing with a ball or foals roughnecking with one another and you should know what sort of behavior I am referencing. If you suppose that this is cheating, all I can do if reference you to the behavior literature on the subject. I think that you'll find that the vast majority of papers will assume a common understanding between the authors and their readership.
Why do some creatures play?
The first think that we should ask ourselves is whether or not this is a well-formed teleological question. As I noted in the previous installment, not all "why" questions are really teleological questions. When we ask "why is the sky blue" we might well be asking whether there is a purpose to the blueness of the sky but we might also be asking for a causal explanation: what processes lead to the perception of blueness in the sky. Let us then reformulate the question so that we can be assured that we are not asking, for instance, for the casual chain of events that cause animals to play (e.g., the stimulation of certain neural clusters caused by the presence of certain environmental factors, etc): what is the purpose of play?
We are interested in knowing the meaning of play, so to speak, and why it is that certain beings engage in it (and, conversely) why others do not. We are not interested in the causality of play. Never the less, we will find our answer by way of etiological questions, although we will do so indirectly. The question, itself, is well-formed, however since our goal is, indeed, to seek a purposeful explanation.
One answer that immediately offers itself is the simple reply that the purpose of play is "fun". Animals and people play because it is fun to do so. This is a poor answer for two primary reasons.
The first reason is that the answer is non-informative. Of course we engage in play because it's fun. It's very nearly a tautology since "fun" is one of the aspects that define whether or not a particular behavior is play. The answer immediately leads us to wonder why play is fun. The sort of answer we are looking for &mdash an answer that illuminates the question in such a way as to grant us a fundamental insight into the purpose of play &mdash will have to be found at a deeper level.
The second reason that fun doesn't suffice as a teleological answer is that it is, in fact, an etiological answer. To say that we play because it is fun to play is to propose a causal chain. Adding some links to the chain will help to make this linkage explicit:
- Engaging in the type of behavior known as play causes certain neurochemical interactions
- These neurochemical interactions lead to the formation of the euphoric mental state known as "fun"
- This euphoric state stimulates an organism's pleasure centers
- This results in a feedback loop where an organism's desire to experience pleasure leads to it performing actions (play) which result in a euphoric brain-state (fun)
Never the less, I believe that a purposeful (i.e., teleological) answer can be find and that it can be found by utilizing science to do so. More specifically, I believe that the best answer can be found in the realm of biology.
Those who may be familiar with either biology or teleology might suppose that I am going to utilize the theory of evolution. This is a reasonable guess given that evolutionary biology is, in fact, the one branch of science that produces the most, as well as the best, teleological explanations; however, I want to show how other branches of science can do so as well. The solution that I am seeking will be found in the sciences of genetics and embryology (with a bit of taxonomy) and should, in principle, be able to even convince a diehard creationist.
Before I proceed, I think that it's worthwhile to expand upon that a bit. A creationist will, of course, be inclined to offer the position that all questions should ultimately be answered in terms of God's will. I am reminded of a song I once heard that talks about the flowers and the hills, and so forth. Each stanza of the song ended with the words "because the Lord God made it so!"
We might suppose that if one thought that the answer to all questions was ultimately to be found in the will of God then science would, by definition, be excluded from providing any teleological answers; however, even if we do accept such a proposition it is still possible to ask (and answer) teleological questions that don't require us to resort to God by way of answer. Let me offer an example.
Suppose that I built a car and you wanted to know why the car included a break pedal. I could say that the break pedal is in the car because I so willed it. This would be a perfectly factual answer (and a teleological one at that!) but I suspect that you would find it uninformative. You aren't really interested in knowing who put the pedal there and you already know that whoever did put it there did so as an act of creative will. What you really want to know is the reason the car includes a break pedal. Simply saying that it is an expression of my will is uninformative. The answer you want is more likely to be something like this: the break pedal is there because it is a part of a system which allows the operator of the car to retard the car's momentum, thus allowing the driver to more easily drive the car without causing it to crash.
This second explanation is an example of a "functional teleology". Note that even though we sincerely believe that the car has a creator, we can find a satisfactory explanation that doesn't requires us to make reference to the creator. In doing so, we are neither denying nor affirming the existence of the creator (nor offering any comment upon additional teleological layers to the question).
Many theists have adopted the supposition that science doesn't seek divine answers to be a tacit endorsement of atheism. As we can see in this example, this is a poor assumption. Science seeks functional answers. Just as the question of a car's break pedal demonstrates that functional answers can be informative and even preferred, science strives for functional explanations precisely because such explanations are informative and useful. The fact that science doesn't try to seek explanations in the realm of the metaphysical or the theological does not mean that science is taking a stance on either subject &mdash quite the contrary.
As for the question at hand, if it is your preference to view play as, ultimately, being an expression of the will of God, so be it. I will only attempt to approach the question from the perspective of a functional teleology while leaving the matter of God's will (and existence) for some other time.
Let us begin our investigation into the question of play with a survey. We do so because it is evidence that many organisms do not engage in play. Fanciful tales to the contrary, plants do not play, nor do protozoans, fungi, amoebas, and so forth. Play is strictly limited to the kingdom of animals.
We can exclude from consideration those animals that lack brains such as starfish and sponges, or which only have the most rudimentary of brains such as insects and mites. Rather than proceeding in a haphazard way, let us do a more methodical survey using cladistics.
Cladistics is the science of partitioning the natural world into hierarchical groups (that is, into a taxonomy). At this point, some may believe that I'm about to break my promise of offering a teleology that would even satisfy a creationist. While modern cladistics does rely heavily upon evolutionary theory, even creationist theories utilize taxonomic relationships (all cats are felines, all felines are mammals, are mammals are vertebrates, etc). Indeed, the father of biological taxonomy (which later became cladistics), was a creationist (by necessity, being a predecessor of Darwin's). Since I'm only using cladistic partitions to help us narrow our search, I have not broken my word.
Being vertebrates we have a natural tendency to divide the animal world into vertebrates and invertebrates; however, this is largely the result of a parochial perspective. The vast majority of animals are invertebrates. Vertebrates aren't even a phylum (the largest taxonomic division among groups of animals) but rather a subphylum of chordates. For us to see animals as being divided by vertebration would be like the citizens of the island of Tonga dividing the people of the world into Tongans and non-Tongans.1 While this is a factual division, I suspect most people would be amused to suppose that being a non-Tongan said anything significant about them. Be that as it may, let's indulge our parochialism and first consider invertebrates if only to dispense with a large chunk of candidates.
The phenomenon of play does not appear to be a part of invertebrate (that is, 16/17ths of the world's phyla) behavior. Of all the invertebrate species, the only potential case might be octopuses (and yes, folks, that is a proper pluralization of the word octopus). Although octopuses are very remarkable creatures that exhibit some truly extraordinary behaviors &mdash including the ability to open sealed jars and to escape from fish tanks &mdash the only examples I've found for play among them is strictly anecdotal. To the best of my research, I haven't found any credible observations of octopus play and am inclined to view the anecdotal accounts with deep suspicion.
Let us narrow the focus to our own little corner of the biological world and consider play about those creatures that have a spinal column.
Do fish play? It seems not. How about amphibians? No. Perhaps reptiles? No. Birds? Apparently not, although they do engage in complex behaviors that sometimes seem to have a near resemblance.
Mammals do play. More precisely, some mammals play. Many mammals do not.
At this point, rather than trying to survey the various orders of mammals (which would be a huge task), I'm going to reformulate the question by asking what types of mammals play. For this purpose, I'm going to take a random sample of creatures that do and do not play and ponder the question of what, if anything, distinguishes them.2
Before doing so, however, I am going to give you the opportunity to do the same. See if you can identify any patterns that distinguish between mammals that play and mammals that do not. Meanwhile, I will pick up the thread during the next installment, two weeks hence.
1 Some might protest that vertebrates are special given that all large animals are vertebrates. Discounting such extinct examples such as a six foot long sea scorpion, it is true that having vertebrae is a definite advantage when it comes to size. However, this is nothing more than picking a particular feature and extolling it arbitrarily. Besides, the very largest organisms aren't animals at all, they're plants &mdash which certainly don't have vertebrae.
2 Hint: I'm not necessarily looking at the species level.