difficult to perceive

See: impalpable
References in classic literature ?
Nor is it difficult to perceive the tendency of this abandon-to elevate immeasurably all the energies of mind-but, again, so to mingle the greatest possible fire, force, delicacy, and all good things, with the lowest possible bathos, baldness, and imbecility, as to render it not a matter of doubt that the average results of mind in such a school will be found inferior to those results in one (ceteris paribus) more artificial.
In fact, it was not difficult to perceive that his most devoted attention awakened no acknowledgment, and that the grace with which he rode one of his most fiery horses was thrown away, for it was only casually and by the merest accident that the princess's eyes were turned towards him.
I answered all her little questions; she prolonged her talk, I went on following its many little windings; she sat so long, said so much, varied so often the topics of discourse, that it was not difficult to perceive she had a particular aim in thus detaining me.
These ladies were graceful and handsome; and it was not difficult to perceive at a glance that even their presence there, had a highly beneficial influence on the patients who were grouped about them.
For a nation well accustomed to religious intolerance as that catalyst galvanizing communal hatred between various communities, it is not too difficult to perceive the brand of bigotry advanced by Modi & Co as a factor that could further undermine the unity of the country.
When sitting at the keyboard, it is difficult to perceive wrongness without wanting to scratch it with a caustic retort.
Individual pitches and individual loudness will be difficult to perceive, and the tone combination will have an inherent roughness as a result of this uncertainty.
While the answer may not be difficult to perceive, the strategy in this regard primarily revolves around developing stakeholders of all concerned in the project.
By today's standards, it is very difficult to perceive the bygone array of different businesses, all of which operated so close together.
It is difficult to perceive how this witness had no ill motive in testifying.
If the image is large but dim, it becomes difficult to perceive subtle differences of contrast and color.
As credit cards allow payment at the end of the month without incurring interest, consumers found it difficult to perceive the advantages of charge cards when compared to credit cards.