In the legal term “probable cause”, both “probable” and “cause” are used in a basically Aristotelian way. Legal reasoning in general is — or ought to be — a specialized kind of hermeneutics. It is fundamentally dialectical in the Aristotelian sense. The intent of a law is matter for interpretation.
Things Aristotle calls “probable” have nothing to with statistics. The legal notion of “probable” cause is much closer to Aristotle’s concept of probability. It refers to conclusions for which there are good reasons, but which are not expected to be established beyond reasonable doubt.
Mathematics achieves certainty and rigorous necessity through the artifice of abstracting away real-world complication and ambiguity. Whenever we are concerned with the real world as we actually experience it, whatever conclusions we reach at best follow probably rather than necessarily.
Keeping in mind the probable character of judgment in general should not prevent us from acting decisively. This kind of “probability” is all the basis we need to have well-founded practical confidence. We can have strong confidence without false pretenses of certainty.
To claim certain knowledge in these cases amounts to what Kant called dogmatism. The deep roots of American pragmatist philosophy have more to do with something like an Aristotelian emphasis on the practical sufficiency of probable judgments than with later reductive, utilitarian theories of value. (See also Aristotelian Dialectic; Dialectic Bootstraps Itself; The Epistemic Modesty of Plato and Aristotle; Demonstrative “Science”?; Kantian Discipline; Copernican.)
The works of Aristotle as they have come down to us include what seem to be nearly opposite statements about the knowledge of first principles. Book 1 of the Topics, Aristotle’s treatise on dialectic, says that dialectic, which assumes no pre-existing truth and does not yield certain conclusions, turns out to be the best way to the investigate first principles.
However, striking a much more Platonic note, book 1 of the Metaphysics says that knowledge of first principles or “wisdom” is the most difficult of all, but is also the most exact kind of the knowledge in the strong sense that is often translated as “science”. This is said to include knowledge of goods or ends, along with other sorts of causes. But then again, book 1 of the Nicomachean Ethics insists that ethics and the practical judgment associated with it are necessarily inexact. This latter difference seems to have to do the status of first principles as universals, in contrast to the concern of ethics with particular actions.
While book 1 of the Metaphysics is a beautiful text with many valuable insights, the idea that knowledge of first principles could be what is most exact seems incongruous to me. It seems to assume an unequivocal priority of universals over particulars, whereas I think the overall balance of Aristotle’s work shows a much more even-handed view. The ethics, the dialectic, the biological works all take a more nuanced approach. My favorite part of the diverse collection that is the Metaphysics is the very dialectical part in the middle about substance, potentiality, and actuality. (See also Interpretation; What and Why; First Principles Come Last.)
Discursive reasoning indirectly addresses meant realities by means of addressing things said, on the model of Aristotelian dialectic. The detour by way of examining the commitments implicit in things said turns out to be essential to a non-naive method that has the potential to iteratively free itself of assumptions. (See also What and Why; Interpretation; Kantian Discipline; Dialogue; Iterative Questioning.)