Nothing happens without a reason. This is Leibniz’s principle of sufficient reason (PSR). According to it, every single event in the universe is metaphysically tied to others by some rational link, usually seen as a cause. Causation serves as the unifying force in the universe. Now, cause means, in the broadest sense, reason and ground. The German word Grund captures this triple signification. The phrase could be thus translated as: “everything is grounded” or “everything is rationally grounded.” But what is reason? Logic. The universe is logical in the last instance. Causes can be logically grasped as necessary links. Of course, there are both logical and empirical connections between facts. To assert the unrestricted validity of the PSR logic/reason, and being must coincide. Following Leibniz, the distinction reason/being is derived from our finite point of view. Seen from God’s perspective, facts are as necessary as logical judgments.
According to Leibniz, the world is logically bound. This metaphysical thesis is grounded in our capacity to express all phenomena in a single logical system. That is, the world should be fully expressible in a set of homogeneous, logical terms. This is what grants the unity and consistency of being. Logic is a symbolic system in which facts are expressed in propositions connected through defined elements (connectors), in which several transformations are possible as long as the value called truth is preserved. This last element is called entailment. Entailment is the logical form of causality or, more broadly, ground.
But what would happen to entailment, truth, and the principle of sufficient reason if there were different logical systems? This is not just a theoretical question; we already possess various logical systems. We have to count on certain logical pluralism. This is the first trait of our contemporary logical horizon. The other one is logical limitation, i.e., the fact that every logical system, and in fact, every axiomatic system, is either incomplete or inconsistent.
What happens when we consider these two conditions: incompleteness or inconsistency, and the plurality of logic? On the one hand, there is something beyond the scope of pure formalization; on the other, there is the fact that formalization can be carried out in different ways. This situation exceeds the classical pretensions of the traditional logica universalis—a single, complete, and consistent system capable of representing all facts (beings and their reciprocal connections) in the world.
However, this does not result in unbridled pluralism, nor does it disintegrate logic as a whole or the concept of logical implication. Instead, logic is defined more broadly, while still avoiding arbitrariness. The result is what we call the principle of insufficient reason, where logic is recognized as both limited and plural.
This is the logical path to the principle of insufficient reason. But there is also a natural-metaphysical one. It should express how the concrete world is neither determined nor undetermined but subdetermined in its very actuality. Or, to put it differently, it is determined but not to such an extent that its potentialities are exhausted. An actual thing is both determined and open, concrete and possible. To phrase it differently, it is overdetermined, i.e., subject to different layers of determinations, and subdetermined, i.e., open to more determinations, both quantitative and qualitative. We can take this a step further. Things in the world are subject to change: from atoms to societies, galaxies, and living organisms. There is a history associated with every concrete. This history exhibits patterns and regularities, invariances and symmetries, but never ultimate rules.
From here follows that there is no necessary being. And yet, being is not arbitrary. Once something exists, it is bound to other beings, as well as its own past. It is bound to its environment and the links it has established with other beings. Jumps are relative. In our universe, several forms of conservation exist: matter and energy, at least. This means only that nothing comes from nothingness. There is a tie between being and being. Even if the meaning “to exist” changes throughout evolution (for example, an atom, numbers, and memories do not exist in the same fashion), there is always a mixture of continuity and discontinuity.
The existence of tangible and definite entities does not preclude the prospect of transformation, even dramatic metamorphosis, in individuals or collectively. There is no primitive void out of which everything emerges, as from the guts of some god. Things originate from other things. However, if things possess the ability to evolve and innovate, it is because they are never complete or final, i.e., purely present things, but rather ongoing processes. Through information, they may retain the past (memory) and cast possible future (projection) outcomes, as well as enter processes of morphogenesis and transformation. Things are beyond things, more than themselves.
The concept of ontological difference was introduced to save beings from absolute closed immanence, from the fate of being always the same due to the powers of some essence. Being meant timely existence, becoming, and transcendence. But this concept deprived beings of the power to become others by themselves. The principle of insufficient reason restores this power to things. The powers of being belong to beings. They are not modes of appearance but being itself, distributed among beings and connections, states and processes, individuals and domains, scales and modes. Being is therefore not before beings (ontologically, as in Heidegger and his pupil Badiou), but among them. It is their link and the possibilities of radical novelty that inhabit them.
Insufficient reason means not an indeterminate but a subdetermining reason. A determination that does not exhaust future possibilities. These are not prefigured as in the roll of the dice, where we know a priori that six and only six possibilities exist. Things are fully determined in the sense of fully concrete, but subdetermined as they can always be otherwise: play another role, show another perspective, evolve, separate, mix, experiment metamorphoses, or generate new beings and relations.
But what to do with so many logics and worlds, beings and connections, facts and interpretations? Several descriptions and frameworks for interpreting the world may be equally valid, supported by evidence or experience. Several may be similarly consistent. How to decide? For its ethical consequences. The principle of insufficient reason demands to do justice to logic and facts, to determinateness and to openness, but also to ethics. The ultimate descriptions of the world remain undecided, being only possible, and thus require the intervention of ethics.
References
Badiou, A. (2017). Being and event. Bloomsbury Academic.
Heidegger, M. (1996). Being and time (J. Stambaugh, Trans.). State University of New York Press.
Rescher, N. (1992). G. W. Leibniz’s Monadology. Routledge.
