Is science a sandwich?
For starters, I think it’s important to debunk the idea that science consists of discovering things that are already there, as though the Actual Rules of the Universe were just out there waiting for someone clear-sighted enough to perceive them. Don’t worry, I’m not going all Parmenides; there may be something out there, and our science may closely approximate it. But in no case can we interact with truth directly without using science as an interpretive tool. In effect, truth is a theoretical entity, something it seems reasonable to believe in but with which we cannot interact. It is more useful, then, to talk about the verifiable qualities of a theory –- how well it predicts, how well it explains –- than to question whether it "describes reality." If science amounted to drawing a complete map of a well-defined territory, then we could critique a scientific theory on the basis of how well it accords with reality. But to launch such a critique, we would need access to the territory. Instead, we must (and do) treat science as our best means of navigating a territory we cannot see. And it’s foolish to imagine that there’s only one way to do this, or any significant difference between the best version of one method and the best version of another. Very good echolocation versus very good feelers? The distinction is minimal.
To imagine that all scientific discoveries thus far would have inevitably been made, changing only the order, assumes that there is a way that science must look. This assumption isn't justified if you view science (as I do) as "the best explanations we can manage" rather than "an explanatory system that is coextensive with reality." Of course we always try to get theories that have more predictive value, but we can do that in a number of ways; there's no "true" version of science. And since a lot of discoveries are predicated on others, changing the timing could change a great number of things. For instance, we might have discovered relativity without Einstein, but we might just as easily have come up with a theory that worked equally well but wasn’t exactly the same. In fact, given that the scientific context would be so different -– imagine getting through the early 20th century without relativity, if you can cope with counterfactuals! Imagine, just for starters, the state of technology! –- it’s reasonable to assume that this other theory wouldn’t look exactly the same. It would give us another method of navigating the unseen territory. The only way we could imagine that 1950s relativity would look exactly like 1910s relativity would be if we assume that science is purely a process of discovering things that are Really Out There, of making our map look more like some verifiably existent landscape.
Saying that "science is developing towards an understanding of the world" is like saying “the human race is evolving towards an organism that is well-adapted to its environment." It is understood that the evolution is not complete, but also that there is no one thing that "complete" would mean, no one thing that this well-adapted organism must look like. There is no reason to imagine that the current state of the species represents the only way we could have adapted to the environment on Earth. Why must the smelling mechanism be on the face? Why round pupils, and not oval (like a cat) or rectangular (like a goat)? What’s so maladaptive about a tail, or feather-like plumes on the head? They’re not as harmful as an appendix, that’s for sure, and yet we’ve got one of those. The human race could have had any number of different traits without significant harm, and there are any number of ways in which we could have achieved the useful traits we have today (for instance, it’s important to have jointed limbs, but why must the joints only go one way? Why one ball-and-socket and one hinge per limb?). We are adapted to our environment because we evolved this way, but we didn’t evolve this way because it was the only way we could have ended up adapted to our environment. To say so is effectively to say that there is a blueprint for an effective human race (not necessarily that there is a designer, mind you, but that there is only one good design). Either evolution is teleological, or it could have happened differently.
It’s easy to look at some of the hypotheticals I’ve been posing and to say, for instance, "well, pretty much all mammals have one ball-and-socket and one hinge joint per limb." This is important. Because we evolved from other mammals, we retained certain characteristics of those animals that were useful or at least not maladaptive. A change somewhere far back in the game -– maybe Tiktaalik grew an extra leg, for no really good reason except that there was no reason not to -– might have altered all subsequent development. Make it two extra legs, actually, because symmetry is useful. Natural selection would then select among six-legged forms, not four-legged ones, and subsequent developments would be based on that model. It would be pretty far-fetched to imagine that you could somehow get a bipedal human out of that! And yet we would have evolved based on exactly the same processes.
The same is true of science; a change in scientific history might have had a profound effect on our current theories, but it would not mean that we didn’t end up with the most useful theories possible based on the history we had. That’s how science works: as Bas Van Fraasen said, "Do not ask why the mouse runs from its enemy. Species which did not cope with their natural enemies no longer exist. That is why there are only ones who do." Only scientific theories with the best predictive and explanatory power, based on what we know, can survive – but that doesn’t mean that the theories we subscribe to now are the only useful theories we could have developed, any more than the evolutionary need to flee predators means that a mouse couldn’t have had pointy ears.
Viewing science as an evolutionary process makes it clear that we cannot logically conceive of science as aiming for truth, any more that we can consider an individual species to be aiming for a completely evolved form. More importantly for the current debate, we cannot assume that the current state of either science or species represents an inevitable conclusion. The goal is to be adapted and to be adaptable, not to accord with an inaccessible Truth or an invisible Design. There is more than one way to do this, and any change in path would have altered background and context so much that we might end up with something completely alien to what we know now (but, importantly, still about equal in adaptiveness/usefulness!). To claim otherwise, to claim that any scientific advance that’s been made so far would have been made eventually by someone regardless of altered time or background, is to claim that there is only one thing that science can be.