In this artwork, how is the Subject matter discussed?
While the traditional title Philosopher in Meditation has to a large extent been responsible for the painting's popularity, it is iconographically untenable. The painting shows none of the conspicuous attributes of scholarship or philosophy—books, globe, scientific instruments, etc.—and the presence of at least one other figure involved in domestic tasks does not fit in with the solitude associated with study and meditation. Though a large book and a quill seem to be among the few objects on the table in front of the main figure, they are summarily depicted and impossible to identify more precisely: a Bible alone would not suffice to make the figure depicted a scholar or "philosopher." Staircases—whether spiral or not—were not an attribute of philosophy in the early 17th century. Similar observations argue against identifying the main figure as an "alchemist," a subject that would allow for other figures, such as an assistant tending a fire. 
The objects depicted suggest a domestic setting, yet the improbable architecture speaks more for a history than a genre subject. The French art historian Jean-Marie Clarke argues that the scene is ultimately derived from the Book of Tobit, one of Rembrandt's favorite Old Testament sources. The sole objection to this interpretation is that, apart from the two main figures—the blind Tobit and his wife Anna— there is no typical iconographic attribute, specifically Anna's spinning wheel. Nevertheless, a plausible interpretation of the scene is Tobit and Anna waiting for the return of their only son, also called Tobias, a scene that Rembrandt had already represented in another version in 1630, in which Anna's spinning gear is minimally indicated. This is supported by an 18th-century source identifying a Rembrandt painting of exactly the same format representing a "Composition with Tobit and a winding stair." The Rembrandt Research Project dismisses this evidence as "certainly incorrect since there are two women in the picture and there is no specific motif from the story of Tobias-" Earlier inventory mentions of a "winding stair with an old man sitting on a chair" or "winding stair" attributed to Rembrandt are vague and might even refer to the companion painting long attributed to Rembrandt, but now given to Salomon Koninck.
Although the title in the Louvre's publications remains Philosophe en méditation  catalogues of Rembrandt's painted oeuvre, starting with Bredius (1935) identify the subject more soberly as a "Scholar in an Interior with a Winding Stair." With the rejection of the attribution to Rembrandt by the Rembrandt Research Project in 1986, the title became "Old Man in an interior with a winding staircase."
alchemist Book of Tobit Louvre Old Testament Rembrandt Research Project Rembrandt Tobit Salomon Koninck philosophy