1593, kept seven years in prison, and finally burnt at Rome in 1600.

Campanella, likewise an Italian, who spent twenty-seven years in a dungeon
for having conspired against the Spanish masters of his country, and who
died in exile in Paris in 1639, was a sceptic in philosophy, or rather an
anti-metaphysician, and, as would be said nowadays, a positivist. There are
only two sources of knowledge, observation and reasoning. Observation makes
us know things--is this true? May not the sensations of things which we
have be a simple phantasmagoria? No; for we have an internal sense, a sense
of our own, which cannot deceive us, which affirms our existence (here is
the _Cogito_ of Descartes anticipated) and which, at the same time,
affirms that there are things which are not ourselves, so that coincidently
the ego and the non-ego are established. Yes, but is this non-ego really
what it seems? It is; granted; but what is it and can we know what it is?
Not without doubt, and here scepticism is unshakable; but in that there is
certitude of the existence of the non-ego, the presumption is that we can
know it, partially, relatively, very relatively, while we remain infinitely
distant from an absolute knowledge, which would be divine. Therefore let us
observe and experiment; let us make the "history" of nature as historians
make the history of the human race. And this is the simple and solid
philosophy of experiment.

But Campanella, like so many more, was a metaphysician possessed by the
devil of metaphysics, and after having imperiously recommended the writing
of only the history of nature, he himself wrote its romance as well. Every
being, he said (and the thought was a very fine one), exists on condition
of being able to exist, and on condition that there be an idea of which it
is the realization, and again on condition that nature is willing to create
it. In other words, nature can, knows what she wishes, and wishes. Now all
beings, in a greater or less degree according to their perfection or