Descartes: A Biography

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AFabulous World (–) 

Descartes told Mersenne the following year that, when he first arrived

in the United Provinces, he worked almost single-mindedly at trying ‘to

demonstrate metaphysical truths’. ‘The first nine months that I spent in

this country, I worked on nothing else, and I...had planned to put some

of it down on paper. However, I do not think it is appropriate to do so

until I have first seen how my physics is received’ (i.). This treatise

was written in Latin, as were theMeditationsinto which it later devel-

oped, and it addressed the same two questions that eventually became

the focus of the latter work, namely, ‘the existence of God and that of

our souls when separated from the body, from which their immortal-

ity results’.Descartes’ natural diffidence about metaphysical questions,

especially those that impinged on theologically sensitive issues, may have

persuaded him not to proceed with these metaphysical inquiries at that

time.

Another reason for this decision, suggested to Mersenne, was that many

of the projects that had been initiated at Paris were overtaken by new

discoveries by Descartes or by a change in perspective that was sufficiently

radical that it required him to begin from scratch:

If you find it strange that I had started a few other treatises while I was in Paris, and

that I did not continue with them, I will tell you the reason why. During the time

that I was working on them, I acquired a little more knowledge than I had had when I

began. When I wished to include that, I was forced to undertake a new project that was

rather more extensive than the original one, like someone who begins a building that is

intended as their home and then acquires unexpected riches which change their status,

so that the building that had been started is now too small for them. No one would

blame them if they were seen to begin another building that would more appropriately

reflect their good fortune. (i.)

One of the key items of ‘new information’ was acquired when Descartes

was told about the appearance of parhelia near Rome. This provided the

initial motivation for research directed to what he frequently referred to

as a ‘little treatise’ and which eventually developed intoThe World.

The natural phenomenon of parhelia, or false suns, is a group of appar-

ent spots on either side of the Sun, which are caused by light shining

through ice crystals. It was observed by the Jesuit priest Father Scheiner,

atFrascati onMarch, and reported by Cardinal Barberini to

Gassendi’s patron in the south of France, Nicholas Claudius Peiresc. He

in turn passed on the information to Gassendi, who, during his travels

in the United Provinces, told some of Descartes’ acquaintances about it.