We must reason in natural philosophy not from what we hope, or even expect, but from what we perceive.

We can trace back our existence almost to a point. Former time presents us with trains of thoughts gradually diminishing to nothing. But our ideas of futurity are perpetually expanding. Our desires and our hopes, even when modified by our fears, seem to grasp at immensity. This alone would be sufficient to prove the progressiveness of our nature, and that this little earth is but a point from which we start toward a perfection of being.

Nothing tends so much to the advancement of knowledge as the application of a new instrument. The native intellectual powers of men in different times are not so much the causes of the different success of their labours, as the peculiar nature of the means and artificial resources in their possession.

The whole language of nature informs us, that in animated beings there is something above our powers of investigation; something which employs, combines, and arranges the gross elements of matter - a spark of celestial fire, by which life is kindled and preserved, and which, if even the instruments it employs are indestructible in their essence, must itself, of necessity, be immortal.

The most important of my discoveries have been suggested to me by failures.

In the present state of our knowledge, it would be useless to attempt to speculate on the remote cause of the electrical energy... its relation to chemical affinity is, however, sufficiently evident. May it not be identical with it, and an essential property of matter?

There may be beings, thinking beings, near or surrounding us, which we do not perceive, which we cannot imagine. We know very little; but, in my opinion, we know enough to hope for the immortality, the individual immortality, of the better part of man.