On assumption of rationality

Why metaphysics can only be applied under the assumption of rationality?

Yesterday I read an interview with a well-known and at the same time extraordinarily talented expert in international politics. He very soberly noted (thus showing considerable self-awareness) that as an analyst, he can only make forecasts based on rational scenarios. He can, for example, analyze the decision-makers of a given state and determine their goals and strategic culture. Then he can examine that state’s environment, identify its strengths and weaknesses, as well as its opportunities and threats. On this basis, he creates various foreign policy scenarios, assuming the rationality of the decision-makers’ actions.

Why is this assumption of rationality so crucial? Because an irrational decision-maker is unpredictable. First, this unpredictability increases the number of possible scenarios by one or even two orders of magnitude. Under the assumption of rationality, we expect the scenarios implemented to serve the state’s interests, i.e., to capitalize on opportunities and avoid threats. Without rationality, the pool of scenarios also includes those that are detrimental or even harmful to the state. Second, with rationality, we can differentiate between scenarios—some are more reasonable than others. In the case of an irrational decision-maker, reasonableness is not a criterion: they can do absolutely anything.

This reminds me of the situation we metaphysicians find ourselves in. It’s entirely possible that metareality conceals something utterly irrational, unpredictable, or even absurd (at least from our perspective). The universe might be a sophisticated joke, an oversight by a demiurge who forgot to dispose of it, or a simulation serving completely incomprehensible purposes for a civilization far more advanced than ours.

We cannot dismiss such possibilities, but we also cannot do anything with them. If we reject rational attempts to explain metareality, we become flooded by thousands of disordered scenarios. Worse yet, we lose the tool that allows us to evaluate and compare them. Thousands of theories without a way to rank or differentiate them is a recipe for chaos, and for the end of metaphysics as a field of knowledge. In such a state, metaphysics would no longer be about understanding, but rather just collecting all possible explanations, no matter how wild, improbable, or absurd they might be.

However, if we decide to accept that there is a rational answer to the question “What is the content of metareality?” then suddenly it turns out that there is also a rational method for systematically comparing metaphysical systems—ranking them and choosing the best. This method involves evaluating a system based on two characteristics: the “weight of assumptions” and its “heuristic fertility.”

By “weight of assumptions,” I mean the number and the qualitative burden of the assumptions we must accept. The more assumptions and the more problematic they are, the worse it is. We prefer to assume as little as possible because the fewer assumptions we make, the less chance we have of being wrong. It’s somewhat like mathematics: the more axioms we have, the greater the risk that some pair might be contradictory or that an axiom might be poorly formulated.

By “heuristic fertility,” I mean the system’s ability to explain the issues that interest us. Any metaphysician can name at least ten problems they find most intriguing. The more questions a theory answers—and the more comprehensive these answers are—the better. Again, this is analogous to mathematics: we want a set of axioms that allows us to prove and demonstrate as much as possible.

We can estimate both values to a fair degree. In the case of assumptions, we can list them, assign weights to each, and sum them up. For heuristic fertility, we can select a set of questions, assess the quality of the answers, and sum those as well. The ratio of heuristic fertility to the weight of assumptions gives us a measure of a system’s quality.

Having such a metric, we can apply it to every known metaphysical system. A sorted list provides a ranking—the system at the top is currently the best choice due to its highest quality.

Of course, this method is not fully objective, because philosophers value assumptions and solutions differently. What seems obvious to one might be rejected by another. Still, I believe this is the best method available in metaphysics, even if it’s not perfect. In this sense, it resembles democracy, often described as a poor system of governance, yet still the best among those that exist.

Sponsored by: Wiadomości giełdowe GPW