French epistemologist and philosopher of science. There are two Gaston Bachelards: the severe philosopher of science who lays out the philosophy of concepts and "epistemological breaks," and the self-indulgent literary theorist who reverted to phenomenology (the very subject he already criticized in his work on science, no less).
Gaston Bachelard I
Bachelard's works on the philosophy of science ("Essai sur la Connaissance Approchee, New Scientific Spirit, The Philosophy of No: a new philosophy of the new scientific mind", and "Rational Materialism") emerged from studies of relativistic and quantum revolutions, given his background in mathematics and physics.
Bachelard’s study of the rise of scientific objectivity emphasized discontinuity in science, anticipating some of the insights of Karl Popper and Thomas Kuhn: science develops through a series of discontinuous changes called epistemological breaks, which overcomes epistemological obstacles (the methodological and conceptual features of common sense or outdated science block the path of inquiry), a non-continuous history of science where concepts emerge from earlier concepts through a process of correction and rectification. This sort of history traces the emergence of these concepts and reconstructs the breaks that made it possible. Therefore, there is no such thing as an "earlier version" of a modern concept, but a different conceptual framework that defines the different objects of knowledge that may be evaluated in the light of later developments. E.g., the term 'electricity' is used within the physics of the eighteenth and nineteenth century, but the transforming configuration of knowledge meant the concept of electricity also changed dramatically.
However, despite these revolutionary discontinuities Bachelard still believed in scientific progress. Even though each scientific framework rejects its predecessor as fundamentally flawed, the earlier framework may contain permanent achievements that are preserved as special cases within the subsequent frameworks (e.g., Newton’s laws of motions are special limit-cases of relativity).
Bachelard thought the majority of philosophy should be rejected, given that they depend on outmoded scientific philosophy and that modern science cannot, nor ought it, be restricted to one single doctrine (whether it is idealism, realism or even positivism). The only scientific philosophy of the philosophy of physics is, for Bachelard, a "philosophy of No", which denies allegiance to any doctrine and advocates an 'openness' that coheres with the 'open-ended' and 'unfinished quality' of scientific progress itself. The negation is necessary because the scientific attitude must be flexible and adaptable in order to revamp his or her entire framework of reality. There is no destruction, because the philosophy of no actually consolidates what it supersedes.
Bachelard based his philosophy of science on "non-Cartesian epistemology", (against the demand knowledge must be founded on the incorrigible intuitions of first principles) since all knowledge claims are subject to revision and open to new evidence. Particularly, Bachelard rejects naive realism that determines reality within the terms of the given of ordinary sense experience that ignores ontological constructs of scientific concepts/instrumentation. Nor did Bachelard endorse idealism, but instead, an "applied rationalism" that acknowledges the dynamic role of reason in the constituting objects of knowledge, while agreeing that any constituting act of reason must be directed towards an already (antecedently) given object. Both mathematics and the empirical world are complimentary: math should not be seen as the mere language of physical laws, nor should it be taken as an frozen system of ideas, for it is ‘committed,’ and the empirical world shouldn’t be merely a chaos of discrete quanta of data. The investigator does not passively discover the scientific hypotheses and facts, for he creates them: his rational powers and the physical world both construct a holistic reality beyond the naively empirical one.
Gaston Bachelard II
Despite denying the objective reality of the perceptual or imaginative worlds, Bachelard took the time to analyze their subjective and poetic significance. Bachelard's reputation owes more to his studies of poetic language, daydream, phenomenology and their application to instances in the history of science than his work on "anti-positivism" and "epistemological ruptures." The second Bachelard produced works ("L'Eau et les reves, Water and Dreams: an essay on the imagination of matter, La Terre et les rêveries du repos, La Terre et les rêveries de la volonté") on archetypal dreams and daydreams associated with the themes of water as repose, air as movement, and earth as will power/work and rest. Bachelard proposed a "law of four elements" where all images are related to earth/air/fire/water (Empedocles' fundamental forms of matter).
Bachelard thought the projection of subjective values/interests in the experience of physical world were impediments to knowledge. In his "Le Nouvel espirit scientifique", what Bachelard described as the "psychoanalysis of knowledge" explained how the rise of objective/quantified science required depersonalization, abstraction, emotional restraint, and taciturnity. Not to discredit subjectivity, though, Bachelard thought highly of reverie and saw it as the source of great poetry, abject sentimentality, and imaginary physical theories. In the works on both reason and imagination, the creative role of the mind plays a crucial part. In art, "the subject projects his dream upon things," and in science, "above the subject, beyond the immediate object... is the project." He understood the condition of scientific productivity was an affective engagement with things.
To be precise, "psychoanalysis" in Bachelard’s vocabulary does not invoke the Freudian analyses of sublimated drives but the disclosure of archetypes (Jung’s studies on alchemy influencing the interpretation of early chemical theories/practice of alchemy) that inspired the study of reverie, or daydreaming. Inasmuch a daydream is beyond the dreamer's control, there is a flicker of consciousness in daydreaming that generates poetic images as the daydreamer discovers an ideal world. The poetic image yields a sense of wonder and discloses an imaginary world of delight as well as universal archetypes, and allows us to read or listen to a poem as if we were hearing words for the first time. This poetic image is an expression of the basic human characteristic of 'imagining.' According to Bachelard, daydreaming is the function of Jung's "anima" (the female principle of repose) that allows us to reach the sleeping waters that lie within us when we are deep in reverie.
In "La Psychanalyse du feu", the study of eighteenth century experiments with fire, Bachelard showed how the phenomenology of fire as the painful/dangerous/soothing/purifying/destructive/symbol of life and passion determined scientific discourse. The other studies on air, water, earth also as the subject of scientific inquiry have been deconstituted, being dreamt by eighteenth century. The books on imagination and poetic imagery analyze the significance of archetypal images.