Earlier this week I posted about an exchange between philosopher Julian Baggini and theoretical physicist Lawrence Krauss on the question “philosophy v. science: which can answer the big questions in life?” Krauss’ arguments, as they have a tendency to do, bothered philosopher of science Massimo Pigliucci, who has taken the time to summarize his points in a post on his blog, Rationally Speaking. 

If there were required reading for this blog, Pigliucci’s essay would be included, so I urge you to go read the entire thing. The relationship between science and philosophy is foundational to all other issues, and rarely have I seen it so clearly defined.

Here’s a taste (it’s a long essay):

… Krauss aims his response straight at moral decision making: “Getting to your question of morality, for example, science provides the basis for moral decisions, which are sensible only if they are based on reason, which is itself based on empirical evidence.” Seriously? I would have thought the other way around: “empirical evidence” isn’t something that stands on its own. Facts are facts only within a given theoretical framework (as Darwin famously observed), and reason and evidence better play with each other in a mutually reinforcing fashion. It just isn’t as simple as “just the facts, madam.”

Krauss continues: “Without some knowledge of the consequences of actions, which must be based on empirical evidence, then I think ‘reason’ alone is impotent.” Well, yes, but I don’t know any philosopher who would claim otherwise. Let’s say you are a consequentialist when it comes to moral decision making. You do rely on empirical evidence (broadly construed, more on this later) to make specific decisions, because after all you care about the likely consequences of your actions, so you need some way to estimate what such consequences might be. But the prior decision to adopt a consequentialist stance in ethics is not the result of “facts,” it derives from your philosophical reflections on what ethical judgments are and how best to carry them out. You need to read Mill, not Einstein.

But of course Krauss has drunk the [Sam] Harris cool-aid in full: “Ultimately, I think our understanding of neurobiology and evolutionary biology and psychology will reduce our understanding of morality to some well-defined biological constructs.” He, like Harris before, confuses an understanding of the mechanisms of X with the epistemic status (true, not true, undecidable, etc.) of X. To see the point simply, imagine if a neuroscientist told you that he wanted to scan your brain while you were trying to demonstrate the Pythagorean theorem. Said neuroscientist would be able to tell you all sorts of fascinating biological facts about which parts of your brain were involved in the task, how much of each neuropeptide you were using while carrying it out, etc. What he would have absolutely nothing to say about is whether you got the proof right. You’d need a mathematician for that.