Focus on this artwork and explain the Rembrandt Research Project: disattribution and re-attribution.
In the second volume of its Corpus of Rembrandt Paintings, which covers the years 1631–1634, the Rembrandt Research Project (RRP) rejected the attribution to Rembrandt of the Philosopher in Meditation. Until then, and except for the "heretical" John C. Van Dyke, this attribution had been unanimously accepted by experts and art historians. The RRP did not introduce any new objective or documentary evidence, but based its judgment on an assessment of Rembrandt's "habits," an appraisal of the painting's style, and the difficulty of fitting it within Rembrandt's production in 1632 or the later 1630s. The RRP did not make any guesses as to who the author of this painting might have been, but relegated it to "Rembrandt's immediate circle, or even to his own workshop." This judgment was criticized by Jean-Marie Clarke who maintained the traditional attribution to Rembrandt and pointed out that the RRP might have had a special stake in rejecting this painting, as the following quote suggests:
"In the later part of the 18th century the painting enjoyed a great reputation in France as Le Philosophe en contemplation, and it helped to determine the image of Rembrandt's art to an unwarranted extent."This disattribution was not accepted by the Louvre and other Rembrandt scholars, and the newly configured RRP has changed its stance since then. In the fifth volume of the Corpus (2011), which covers "small history paintings," the painting is classified without further ado as a "re-attribution" by the director of the RRP, Ernst van de Wetering. The painting was officially re-instated in vol. 6 of the Corpus under no. A86 with the title Interior with a window and a winding staircase and the parenthetical information: "a study in Kamerlicht."   There is no further mention of the issue of perspective that was highlighted by the Rembrandt Research Project in volume II when it disattributed the painting and called it just that: a study in perspective. Considering the fact that it is supposed to be a study, this painting is executed in great detail (down to individual nails in the woodwork) and bears a signature and date. There is no evidence that "studies" or "interiors" with figures but without a narrative were in demand on the art market. The inconsistencies in the Rembrandt Research Project's position do not lend credence to its argument that, here, Rembrandt was working without reference to  iconography.
Louvre Rembrandt Research Project Rembrandt John C. Van Dyke