Full Idea
Even if we grant impenetrability is added to extension, nothing complete is brought about, nothing from which a reason for motion, and especially the laws of motion, can be given.
Gist of Idea
Even if extension is impenetrable, this still offers no explanation for motion and its laws
Source
Gottfried Leibniz (Letters to Burcher De Volder [1706], 1704 or 1705)
Book Reference
Leibniz,Gottfried: 'Philosophical Essays', ed/tr. Arlew,R /Garber,D [Hackett 1989], p.183
A Reaction
When it comes to the reasons for the so-called 'laws of nature', scientists give up, because they've only got mathematical descriptions, whereas the philosopher won't give up (even though, embarassingly, the evidence is running a bit thin).