No Ought from Is

Presenting philosophical concepts is usually easier when they relate to something current, so it’s in some sense a good thing that Neil deGrasse Tyson, the celebrity astrophysicist, has been defending his idea of Rationalia. Before I comment on it, I would like to step back and talk about a British XVIII century philosopher, David Hume, who provided good reasons for why the thinking behind Rationalia is flawed.

Hume, one of the brightest minds of his time, thought and wrote on a range of issues, from philosophy of science, through ethics, all the way to political theory. It is Hume who clearly delineated the problems we face when we infer general principles from observing particular events. It’s also Hume who stated, in his “A Treatise of Human Nature”:

In every system of morality, which I have hitherto met with, I have always remarked, that the author proceeds for some time in the ordinary way of reasoning, and establishes the being of a God, or makes observations concerning human affairs; when of a sudden I am surprized to find, that instead of the usual copulations of propositions, is, and is not, I meet with no proposition that is not connected with an ought, or an ought not. This change is imperceptible; but is, however, of the last consequence. For as this ought, or ought not, expresses some new relation or affirmation, it is necessary that it should be observed and explained; and at the same time that a reason should be given, for what seems altogether inconceivable, how this new relation can be a deduction from others, which are entirely different from it. But as authors do not commonly use this precaution, I shall presume to recommend it to the readers; and am persuaded, that this small attention would subvert all the vulgar systems of morality, and let us see, that the distinction of vice and virtue is not founded merely on the relations of objects, nor is perceived by reason.

Book III, Part I, Section I

Hume’s complaint here is that people have a tendency to assume that some moral truths follow in a straightforward manner from some matters of fact. For example, an abolitionist might point out that slavery creates object-like property from human beings, and thus goes against the idea of equality of all humans. A monarchist might argue that the king, by the virtue of high aristocratic position, or by being a unique leading figure which everyone obeys, is in the best position to lead a stable country. Notice that, while nowadays people are more likely to agree with the first proposition (“slavery should be abolished”) than the second (“monarchy should be restored”), both go from facts (“humans are changed into property”/”a king is the most influential member of nobility”) to statements of principle. What Hume points out is that, while we can reason about whether or not the facts are true, this will not help us in establishing whether the principles are right.

Of course, people who sincerely believe in their principles will often postulate that it’s obviously the case that they follow from their evidence. And while it’s obviously practically beneficial to live in a society in which people don’t believe that murder is fine (since it lowers your chance of being murdered), that doesn’t actually establish that it’s rational. The problem is that “rational” has become – I assume through overuse – a somewhat nebulous term, living somewhere in the semantic vicinity of “espousing a modern scientific worldview” and “affirming humanitarian ideas of liberal societies”. While it’s true that rational thinking has influenced both modern science and morality, rationality itself is simply a matter of following reason – basing one’s worldview on facts and striving towards logical coherence in conclusions. Notice that the matter of morality is completely absent from this picture. The scientific research done by Kurt Blome was no less rational than that carried out by Linus Pauling. And herein lies the problem.

We cannot say – Hume claims and I agree – that evidence or logic would lead us to formulating “better” principles or policies. As scientific facts don’t take any sides, it is not possible to establish norms of behaviour by analysing them. We cannot deduce an “ought” from an “is”.

Here is where the concept of Rationalia comes in. Rationalia is, in Tyson’s own description, a country with a constitution which only contains one sentence:

All policy shall be based on the weight of evidence

The problems with this approach are apparent once we consider the is-ought problem. But first, it’s hard to even say what basing policy on weight of evidence would look like. Who would get to decide what the weighing, or the threshold of certainty is? Assuming everyone can somehow agree on this – which would be interesting, since the choice of, let’s say, 95% certainty seems to be just as arbitrary as 96% – we still wouldn’t have moved forward. We can have all the evidence in the world that a given choice would bring about a given set of consequences, but this still doesn’t tell us whether such consequences are desirable, or whether the choice itself is good. Example: spending n billion dollars on renewable energy sources would offset the effects of global warming as efficiently as letting m million people die from poverty. Should we flip a coin?

The problem that Tyson doesn’t seem to understand is that there is always an element that lies beyond the reach of rationality in making any policy choices.ยน There is always an underpinning principle that guides policymaking, which establishes what it is that we’re trying to achieve – what is the result that we care about? What is the ought? Only with that can we say that, for example, preserving wealth is less important than preserving human life. In refusing to acknowledge this, Tyson continues enumerating supposed advantages of Rationalia, never quite explaining how they follow from no ethical commitments. Thus, he produces numerous paragraphs about how there would be more funding for social sciences, a better science education, freedom to be irrational, and other benefits available in Rationalia, but he fails to explain why they would be there. His post is a good example of failing to analyze one’s position carefully and to note one’s assumptions. And such analysis is worthwhile, because it is one of the tools which can take us from everyday thinking to philosophy.

1. Ironically, he cites the U.S. constitution as an example of a document that doesn’t discuss morals in the very same sentence in which he provides an example of just such a thing – the restriction on the use of the military.