The search for certainty and the illusion of knowing what will happen tomorrow is something that has accompanied philosophical reflections and scientific practices over time.

If we could be certain that tomorrow would rain, or that a war would break out, the decisions we would make today would surely be very different from those we would choose without knowledge of the future. Laplace’s Demon is a character that represents all this very well , where does it come from?

Laplace’s Demon and the Problem of Prediction

The illusion of predicting and controlling what surrounds us is a theme that can be found in much of scientific development. For example, classical mechanics was based on the idea that everything that exists in the universe and nature can be known through mathematical logical reasoning, as well as through a geometric system to measure and predict what will happen.

In other words, class mechanics starts from considering that the universe and nature are governed by a series of initial laws that can be unveiled by humans for modification.

For example, modern astronomy in the West, inaugurated by Newton, has as its antecedent this position.

Who was Pierre Laplace?

Pierre Laplace was a French astronomer, physicist and mathematician who lived from 1749 to 1826 . He is credited with the development of celestial mechanics, worked with Isaac Newton and Galileo in predicting eclipses and discovering new planets. He also participated in the study of some gas molecules and atomic particles.

What Laplace suggested from his knowledge is that, through science, we can foresee and guess the activity of all the behavioural systems that exist. And if not, unpredictability would be just a mistake of knowledge that as such, can be corrected.

In Laplace’s deterministic conception everything can be predicted , and if this is not the case, it is because the knowledge produced by human beings has erred or is not sufficient.

What this means is that everything that exists in the universe is structured prior to and independent of human activity, so that our own actions and everything we are would be predetermined by the laws of the universe.

The Deterministic Demon (by Laplace)

Laplace’s Demon is an imaginary character who has the faculty of knowing the initial properties of all the particles of nature and the universe, with such precision, that he can apply the natural laws to guess what will happen instantly or in a long time; from a precise movement to a work of art (Calabrese, 1999).

In other words, Laplace’s Demon is a deterministic and all-powerful demon , a being who is outside the universe and who has predicted and decided everything that will happen in nature, including, of course, the activity of human beings.

The logic of prediction was not only transcendental in astronomy, the physical sciences, mathematics and the natural sciences, but has extended to the study of human behavior as well as to its intervention.

For example, it has been present in the development of modern medicine, and we could even see how it impacted the traditional way of doing human sciences, as well as economic and financial activity. However, since the development of new scientific paradigms, the Laplace’s Devil has encountered some limits.

From determinism to indeterminism: the end of certainty

The logic of prediction was especially successful while understanding the universe in terms of linear systems, based on a stable cause-and-effect relationship. But when chaos theory and quantum mechanics came to challenge the linearity of all systems, the scientific field also questioned the insistence on applying predictive logic to everything we know.

In very broad terms and among other things, there was a paradigm shift from considering that in non-linear systems (which are complex systems with chaotic and non-cyclical behavior, as in human beings), the initial state is not equal to the final state, nor does it determine it, so they are systems that cannot be predicted.

In the field of science, the universe and nature in general are no longer conceived as a set of laws of general coverage, pre-established by an external being . This is how, from the beginning of the 20th century, there is an important turn where it is considered that, although it is possible to calculate probabilities, there can always be predictive failures. Based on this, some authors consider that an era marked by the end of certainty is being inaugurated, especially in the human and social sciences.

Bibliographic references:

  • Trainini, J. (2003). Towards the need for a new medical paradigm. Argentine Journal of Cardiology, 71(6): 439-445.
  • Calabrese, J. L. (1999). Extending the boundaries of reductionism. Deduction and non-linear systems. Psychoanalysis APdeBA, XXI (3): 431-453.
  • Wallerstein, IM (1999). The social sciences and humanities on the threshold of the 21st century. The end of certainty in the social sciences. UNAM: Mexico.