Specifically, let us consider changes in time.

The alternate timeline, aside from being an accepted subgenre of science fiction, is often used in the transformation genre as a rationale for the change. Perhaps the protagonist hops timelines and occupies a different body. Perhaps, as in Solari's Night Skies Hotel series, the transformations arise as an unforeseen result of different timelines meeting. Whatever the case, the alternate timeline provides a way to visit strange -- or perhaps not so strange -- worlds without the need to really go anywhere.

It's a temptation for the writer, isn't it? Take the present world, make a few changes to get the result you want and voila! Instant worldbuilding! It slices! It dices! It probably sucks if anyone bothers to take a close look at it. The reason I say that is twofold: A great deal of the time the author (and I'm including published ones!) makes the mistake of either not changing the things that should, or changing the things that shouldn't. And sometimes they do both at the same time.

Let's start with a philosophy of history. A simplistic view of history has often involved two competing theories: the Great Man concept, and the one which Asimov's readers would call psychohistory. The differences can be summed up fairly easily. Believers in the Great Man view history as a series of events that would have turned out very differently if specific individuals (who may or may not be male) were different. The fictional science of psychohistory postulates that in a sufficiently large population, the actions of the whole could be predicted even if that of individuals could not. The real version today would be that some things would have inevitably happened regardless of who was or was not there.

Reality is, of course, somewhere in between. Without Phillip and then Alexander, the Persian Empire would not have likely fallen to a bunch of pseudo-Greek barbarians. No Alexander in Egypt means no reign of the Ptolemies, and thus no Cleopatra having a fling with Roman strongmen a few centuries later. So without them, a lot of history changes.

On the other hand, consider Rosa Parks. Brave woman and well deserving of the adulation she's received, but in the grand scheme of things stuff really didn't depend on her. The Civil Rights movement in the US had been ramping up for decades, and it was pretty much inevitable that someone would finally refuse to go to the back of the bus (or something equivalent) and could therefore act as a rallying cry. The boycott of the busses, the marches and rallies had all, in fact, been prepared for, ready to happen when the right moment came, the moment that Rosa Parks decided. It does nothing to take away from the courage it took to decide to be the one to take a stand, but one has to know that if not Rosa, then someone else.

It's history as climate: you can't predict how many tropical storms are going to form in the Atlantic next hurricane season, but you know that there will be a hurricane season. You couldn't predict the Civil Rights movement would be kicked off by Rosa Parks, but you know it would have been kicked off by someone.

An example of what I mean is one that's been used so often, Adolph Hitler's fictional counterparts must be the most murdered characters in fiction. Hitler is a good example of 'Great Man' (in terms of effects on history) meeting inevitable. There's nothing pre-ordained about Hitler's rise to power -- but 1930s Germany being a militaristic dictatorship is something I'd bet good odds on. In the 1920s and 1930s, the social and political realities of the world gave us not only Nazi Germany, but also Franco's Spain, Mussolini's Italy, militarist Japan and (a bit later) Peron's Argentina and a bunch of other governments based on nationalistic macho and an alliance of the military, conservative reactionaries and anti-communist groups. Germany and Japan differed only in degree -- an extremely large degree. They were very much products of their times. Hitler, Mussolini, Franco, Peron and the others didn't cause things so much as take advantage of conditions that allowed them to seize power -- and then cause things.

When you construct your alternate timeline, especially one that deviates in the fairly recent past -- say the last two centuries -- that's something you have to take into account. Think of James Burke's Connections: Unless you invoke dei ex machina like aliens supplying tech or magic, everything in the story's setting must have 'grown' from 'seeds' that were already there. Even with magic (and I'll use that as the generic term, invoking Clarke's Law for the SF-nal supertechnology), any setting's present-day situation will be a reflection of the world that existed at the point where the alternate timeline diverges from reality, and that's going to be seen later down the line.

This, then, is what someone writing an alternate history must be aware of. Some things change, some things won't, and some will largely be the same but different in the details. The key is knowing when you have to step back from your story, look at the larger details, and ask yourself if this makes any sense at all given the change you've proposed. Sometimes it doesn't and you can't help it; like, for instance, if you really, really want the American Resistance led by General William 'Wild Bill' Jefferson Clinton to finally drive out the Nazis from America. But if you can fix it, you should.

Or perhaps you might want to consider not using the alternate timeline trick at all to get the result you want. As cool as it might be to merge with another universe where you are a velociraptor (and otherwise indistinguishable from your normal, unchanged, existence), I'm sorry, but that blows the old Suspension of Disbelief gauge into the next star system. I'd have an easier time with runaway alien nanotech being responsible. Why? Because simply replacing humans with dinosaurs doesn't make any sense. Vast swaths of history will have changed, simply due to physiological realities when looking at a saurian as opposed to bipedal mammalian body and needs, which means that 'you' aren't going to be you at all. Just as 'you' aren't going to be identical to yourself except for a gender change, or that your alternate self lives in a planet where the US Civil War ended in a draw, or where dinosaurs survived in the New World, or imperialistic aliens tried to conquer Earth in 1942.

Another problem to avoid are pointless differences (aside from the main one that differentiates your timeline from ours) that make no sense at all. Here Solari provides some examples: The names of the continents and some other things in his alternate Earths ('Urippe' instead of 'Europe'), people smoking t'habakkoh and drinking hot koko. We get the joke. And yet, the military drives and flies vehicles named Panthers and Rhinos and Vipers. If the cocoa plant and tobacco plant and continents have different names, why do the animals keep theirs? This is exactly the sort of half-baked way of say "This is a different timeline! See? Do ya, hunh? See?" that makes one throw books at walls.

It's not just calling the alien rabbit a smeerp, it's calling it a r'habbit and expecting people to congratulate you on your cleverness. More importantly it's utterly unnecessary. Call the damn rabbit a rabbit if it's the same freaking animal as in our timeline!

This sort of gratuitous name-changing is just a bad idea. It also overlooks the fact that many names are historically contingent; change the person who does the naming, or even their mood that day, and the name is totally different.

I'll use the t'habakkoh as an example. The best origin known for 'tobacco' is that the Spanish used a corruption of the Arabic word tabbaq, a name for various herbs, and applied it to the plant they found the natives in the New World smoking. So there's a lot of history required for that name to arise: You need Arabic to spread to Spain so the Spanish are familiar with the word, you need the Moors driven out of Spain so the Spanish can go off exploring, you need the Spanish to be the first Europeans to come across it, and you need them to then refer to the plant by a corruption of an Arabic word.

If the English had found it first, we might be debating the health effects of smoking pipeweed -- as modern Hobbits no doubt do.

Basically, a lot of things have to turn out a particular way in order for that plant to be named 'tobacco'. It's not like, say, 'blueberry' where, because the thing's berries are blue, the name of the plant is something that you'd expect could be arrived at independently by different cultures speaking different languages. But t'habakkoh? It beggars belief to think that a culture in a different timeline completely, with differences stretching into the far past, would give that plant a name which is basically a typo for 'tobacco'.

I immediately see authors throwing their hands up in disbelief. "What, you're saying you want us to research everything?" No, I'm not saying that. What I am saying is that if you choose to make certain details important, you should take a closer look at them to make sure they aren't dumb. Solari has the alternate version of the tobacco plant mentioned several times, in a rather prominent role, which continually hammers you with the cute naming. It rapidly gets on one's nerves. If he'd simply called it 'tobacco', no problem: We know it's a translation from whatever language the alternate timeline folks are using. If he'd called it something totally different like, I don't know, zigglegorp, well, that's fine, too. We know it's tobacco, or something like tobacco, but they call it zigglegorp. T'habakkoh, on the other hand, is just lame.

The reason I've written this is that I've seen a lot of transformation stories involving alternate timelines, and in far too many of them, this type of thing is so clearly screwed up that I've wanted to rant on it for a long time. So please, please, please: If you do alternate timelines, and it's not a comedy (in which case you can get away with a lot more), try thinking about it. Sometimes, if you think about the changes, a whole other world of ideas can open up for you.

In the next column I'll look at some ideas more closely related to transformation specifically. Some really evolutionary concepts.