The bottom up thinker builds, using his senses and his mind, a picture of the reality around him, of which he is a part. And in building this picture, he is concerned above all with truth. He seeks the truth, the whole truth as near as he can get to it, and nothing but the truth.
He examines, critically, the evidence of his senses. He assembles this evidence into facts or percepts; then he generalizes and integrates them into concepts. He uses logic and reason to seek understanding. He often stops to ask, “Why?”
He finds apparent contradictions puzzling, and wants to resolve them. He seeks to build a store of knowledge which he, and others, can rely on. He uses, when he can, techniques like the scientific method to help him work out what is true and what is not. And when communicating with others, he always strives to be honest. He seeks to persuade by facts and logic, not by sophistries. He is always open to persuasion by facts and logic, too.
The top down thinker, on the other hand, has far less concern for truth and rationality. He tends only to accept new ideas if they fit his pre-existing beliefs. Where new facts are incompatible with his world view, therefore, he must ignore them, twist them or deny them. Evidence that there has been no significant global warming over the last 18 years, for example, won’t disturb his belief that human emissions of carbon dioxide are causing catastrophic global warming. Nor will it quiet his oft-repeated chants that those who point out such evidence are kooks or “deniers,” nor is it likely to prevent him abusing the scientific method in his efforts to deny reality. Psychologists call this effect “confirmation bias.”
So, like the look-say practitioner, the top down thinker finds it hard to go beyond the limitations of what he has been taught. He prefers to stick to his pre-existing superstitions. (The word “superstition” means “over-standing,” and so is directly opposed to “understanding.” I am indebted to Jason Alexander for this insight.) And when a top down thinker communicates with others, he often uses lies, deceptions, fabrications, obfuscations and psychological tricks like ad hominems as key weapons in of his armoury.