Summary: The Philosophy of No

Philosophy of science generally falls into two opposite extremes: either it becomes too philosophical—focusing excessively on general principles, the a priori, and rational values—or it becomes too scientific, confining itself to particular results, the a posteriori, and experimental values.

A new philosophy of science is needed—one that demonstrates under what conditions general principles can lead to particular results, and vice versa.

We must succeed in reconciling empiricism and rationalism: Empiricism must be understood, and rationalism must be applied ¹. Or, in other words: We prove the value of an empirical law by making it the basis of reasoning, and we legitimise reasoning by making it the basis of experimentation ².

This is not a dualism, for empiricism and rationalism are not opposed but complement each other.

Applied rationalism draws lessons from reality and translates them into a programme for realisation. This is why Bachelard defines the scientific rationalism he advocates as the epistemological current according to which application is not a defeat or a compromise. It seeks to apply itself. If it applies itself poorly, it modifies itself. Thus, it does not deny its principles—it dialecticises them ³.

As a result, this type of rationalism is distinguished from others by its open character:

It is the only philosophy that applies itself by determining a surpassing of its principles. In short, it is the only open philosophy. All other philosophies posit their principles as intangible, their first truths as total and complete. All other philosophies take pride in their closure ⁴.

The true philosophy of knowledge is therefore an open philosophy—one that seeks in reality what contradicts previous knowledge. In contrast, philosophers generally tend to regard contradictions to their theories as mere details or as signs of the irrationality of the given, and they do not revise their theses in any way.

Bachelard then clarifies the meaning he gives to the "Philosophy of No", from which the work takes its title: it should be understood that the new experience says no to the old experience—without which, evidently, it would not be new experience at all ⁵.

The Philosophy of No is the privileged epistemological doctrine that allows us to think through and accompany scientific progress. Progress occurs when experiments are organised with the aim of contradicting or invalidating previous experiments, thereby calling into question theories accepted up to that point.

An experiment that merely confirms previous experiments and theories may be useful, but it is not through such confirmation that the march of science can achieve a qualitative leap forward.

The task, therefore, is to organise experiments aimed at disproving or criticising the theories accepted up to that point; it is this approach that drives scientific progress. The Philosophy of No is not, contrary to what its name might suggest, a closed philosophy:

This “no” is never final for a mind that knows how to dialecticise its principles ⁶.

This is not the “no” of nihilism; on the contrary, it is a constructive activity, intended to explore and affirm the fertile nature of experimentation.

Bachelard makes a twofold appeal: to philosophers, he demands the right to use philosophical concepts detached from the systems in which they originated (for example, to employ the Kantian category without being Kantian). To scientists, he asks that they acknowledge their work is guided by metaphysical presuppositions (e.g., concerning the nature of matter, etc.).

Bachelard finds himself dreaming: against philosophers who tend to apprehend reality from a single, overhanging, and all-encompassing perspective, he envisions a philosophy for each problem, each equation—a philosophy of epistemological detail.

¹ La Philosophie du non, PUF, Quadrige, Paris, 1994 avant-propos, p.5
² ibid.
³ ibid., p.7
⁴ ibid.
⁵ p.9
⁶ ibid.,p.10