We've been discussing for decades how important it is to inculcate our students with critical thinking skills. In recent years I sense that we've backed off from that lofty goal (and wrongly so) in the academic world, in favor of a narrowly conceived push for "quantitative reasoning." Whatever this small-minded objective is supposed to accomplish, at its heart it aims desperately to rationalize, pin down, or somehow pigeon hole the rambling, ambiguous, multi-colored blanket of critical analysis. Perhaps this is due to the frustration we experience teaching critical thinking. It's arguable that our first- and second-year undergraduates are at the entryway to critical thinking. They're too young to embrace it fully let alone use it, and with time, another half decade or so, they will be cognitively prepared for critically taking apart problems and analyzing them from a mature perspective. But our students' readiness shouldn't deter us from hammering home critical thinking through example, discussion, reading, and practice. Critical thinking means getting some separation between the problem at hand and taking, all at once, a deeper look and a look from 30,000 feet. It's a lot more complicated than learning to spot a lie through statistics but it's a lot more useful.
I've taught cellular and molecular evolution for over twenty years and about halfway through struggling with the material I came to realize that it's not the "facts" that matter. Students tend to believe what we say, or at least they try to memorize our "facts" for the next exam. But as we conceptualize nano-scale phenomena it becomes apparent that it's what's happening around the edge of the "facts" that really makes a difference. And I think grappling with this means reasoning in an abstract manner.
Here's a simple example. We teach the characteristics of water and how these characteristics influence living systems. This bolus of information is a bit abstract in its own right because we don't "see" surface tension or cohesion. And we don't readily see them in action, for example in the xylem tissue of a plant or the formation of a raindrop. Teaching this material is, in a sense, making the invisible visible. But it goes deeper. To get at the core of understanding the behaviors and properties of water it helps to understand the nature of the molecule. Literally, how do the three atoms interact? How does the electron cloud establish and behave itself? How is polarity the end result and what does this mean? If we can help students grasp these deep abstractions we can help them see more clearly (more analytically) the behaviors of water.
But when we delve into these mysterious (if basic) facts about water we are wading into depths that may take us to a different place than we expected. All of a sudden we're in the territory of how-things-work-and-why. We are in a deeply abstract mindset where a whole new set of connections can be set up. For example, as we consider hydrogen bonds in water we are free to construct a hydrogen-bond model of proteins. And we may see how hydrogen bonds and their behaviors influence not only protein folding and prtotein surfaces, but the complex behaviors of protein molecules. From this vantage point we may understand better, if not fully, the interactions between embedded proteins and the phospholipid bilayer membrane. We free ourselves gradually from "facts" and encounter a world of analogies, connections, and speculative reasoning. I call this wonderful place abstract reasoning. It's a branch of critical thinking that requires a cognitive leap away from textbooks and flash cards. Using it engenders high-level brain function but it also prepares students for future encounters with the abstract, something they will have to deal with the rest of their adult lives.
OK. This was a kind of introduction to abstract thinking, something I hope to pursue in future writing. It's key I think to critical thinking, which demands similar cognitive investment as well as a healthy dose of getting "above" the problem, that is, speculation. I hope to write about the challenges posed by abstract thinking. And most important, this is the first year I'll approach the topic of cellular and molecular evolution by fully embracing this challenge.