The Optica Promota and Spinoza’s concept of focus

Spinoza: Against Hyperbolic Vision There are several points of correspondence between Spinoza’s objections to Descartes’ treatment of the magnification of images in the L’Dioptrique in his letters 39 and 40, and the analyses found in James Gregory’s Optica Promota, but perhaps the most significant touching point occurs in Gregory’s conclusion, where he brings up the lone failings of parabolic mirrors [...]

The Optica Promota, by James Gregory (1663)

A valuable Spinoza resource: we have an on-line photocopy edition of the 1663 work Optica Promota by James Gregory, an edition found in Spinoza’s library of books. One can see the imprint that Spinoza likely looked at. This copy is found here. Not only this, Ian Bruce has supplied us with a marvelous English translation and [...]

Jan Hendriksz Glazemaker…the Glazier

Jan Hendriksz Glazemaker was born in 1619 or 20, married in 1651, and buried Dec 5 1682. Assumed to be the translator of Spinoza’s works into Dutch, on the strength of the evidence from Duijkerius’ Philopater novel, Glazemaker is seen to be a thorough participant in the Van den Enden and Jan Rieuwertsz circle of Cartesian-Collegiant politicists. Nadler [...]

Two more looks at the Rijnsburg Draaibank

[note: the nature of the Rijnsburg Lathe has been resolved: The Rijnsburg Lathe: Like the Sun, not 200 Feet Away] Adding to the post below, here are two more looks at the Rijnsburg lathe, passed on to me by Mr. Verdult who runs the excellent Spinoza resource site http://spinoza.blogse.nl/ A detail from a photo from Theun de Vries’ book [...]

A Closer Look at the Rijnsburg Lathe

[note: the nature of the Rijnsburg Lathe has been resolved: The Rijnsburg Lathe: Like the Sun, not 200 Feet Away] I am still attempting to assess the documentation and authority of the lens lathe at the Rijnsburg Spinozahuis. If anyone has notions of either the historical accuracy of this device, or even the working designs of [...]

How Much were Spinoza’s Lenses and Microscopes?

In the interest of making Spinoza’s lens-grinding, polishing, and telescope and microscope building more vivid to those considering his metaphysics, this evidence is posted as to the kinds of prices for those services one would expect. Lueken and Lueken (1694) E. G. Ruestow writes: At a date I read to be late 1670′s: “…Johan van [...]

Van Leeuwenhoek’s View of Technology and Spinoza

Part of this process of looking into the lensed conception of Spinoza’s metaphysics is understanding how at the cusp of a change in the technological interface - that is, with Descartes, an increased mathematization of nature and its corresponding instrumentization of devices - there also existed alternate conceptions of what viewing, observing and measuring entailed. The idea that [...]

Spherical Aberration: Descartes’ Solution

Philosophical Context: Optics For those unclear about what spherical aberration is, and attempting to follow Spinoza’s comments about Descartes below, it is the tendency of rays at the edge of a spherical lens to refract at a focal length shorter than those near the axis: This tendency is corrected by a hyperbolic lens, as theorized by Rene [...]

Spinoza and Hooke’s Micrographia: The minascule made Large

Look at Robert Hooke’s incredible, and conception-changing Micrographia (1664). And see it as if you are looking at the very book with excellent viewing software, at Turning the Pages Online (click “Turn The Pages”). This book must have struck one as if from another planet. See the overleafs open up into the most extraordinary illustrations of the smallest [...]

Slightly, Re-evaluating Descartes

The Flexed Lens of Hyperbolic Doubt, as it Imaginatively Focuses the MInd   Instead of seeing Descartes as the harbinger of the tremendous severing of the Body and the Mind, as philosophy can be thought to have suffered over the centuries that followed, there are more subtle readings that grasp the cohesive project that Descartes [...]