subtile

Recent scientific discoveries have conferred upon man new powers of investigation, whereby nature has been made to reveal secrets so subtile that they never had been dreamt of before in philosophy.

From Scientific American ● Jan. 13, 2013

At Paris the Universe is seen, compos’d of Vortices of subtile Matter; but nothing like it is seen in London.

From "The Invention of Science" by David Wootton

The question at issue here is one of those profound and subtile ones which cannot be approached by argument, but can be decided only by a seeing.

From Know the Truth; A critique of the Hamiltonian Theory of Limitation by Jesse H. Jones

We find doctors in the first ages speaking to us of God and the soul as material substances, more subtile indeed than ordinary bodies.

From Ecce Homo! A Critical Inquiry into the History of Jesus of Nazareth: Being a Rational Analysis of the Gospels by Paul Henry Thiry Baron d' Holbach

Not by any altruistic agency we may be certain, as we watch the selfish, irritable little beings, but by subtile scent, or as with the vultures, by the jealous watching of each other's actions.

From Jungle Peace by William Beebe

That cause of motion he makes the Materia Subtilis; and the finer or subtiler that is, the better and fitter he conceives it to be to preserve Motion.

From Philosophical Transactions of the Royal Society - Vol 1 - 1666 Giving some Accompt of the present Undertakings, Studies, and Labours of the Ingenious in many considerable parts of the World by Henry Oldenburg

The heavens change by a subtiler movement than the precession of the equinoxes.

From The Atlantic Monthly, Volume 04, No. 23, September, 1859 by Various

No, his temperament needed a subtiler atmosphere than this, rarer essence than mere brutal freedom The East, the Old World, was his proper sphere for self-development.

From Margret Howth, a Story of To-day by Rebecca Harding Davis

It is the subtiler nature of doubt to penetrate the heart more profoundly than confidence, and to underlie it.

From Two Days' Solitary Imprisonment 1898 by Edward Bellamy

Something keener than philosophy, subtiler than Epicurus, pricked Fred, as Minnie vanished into the cloud of snowflakes.

From The Atlantic Monthly, Volume 03, No. 18, April, 1859 by Various

Of the most noysom poyson that euer was mingled with the subtilest druggs that euer were.

From The Palace of Pleasure Volume 3 by William Painter

Truth is a point; the subtilest and finest; harder than adamant; never to be broken, worn away, or blunted.

From Imaginary Conversations and Poems A Selection by Walter Savage Landor

It was this mastery of the interior life, this impassioned voicing of its subtilest secrets, that made Rousseau so irresistibly attractive to women.

From The Friendships of Women by William Rounseville Alger

I can say, from an experience of over a dozen years, that pupils between twelve and fifteen years of age are immensely interested in such discussions, and are capable of making the subtilest distinctions.

From The Moral Instruction of Children by Felix Adler

As for me, Abraham, Isaac, and Jacob are now only the subtilest imaginable essences, which would not stain the morning sky.

From A Week on the Concord and Merrimack Rivers by Henry David Thoreau