The Difference Between the Democritean and Epicurean Philosophy of Nature
The form of this treatise would have been on the one hand more strictly scientific, on the other hand in many of its arguments less pedantic, if its primary purpose had not been that of a doctor's dissertation. I am nevertheless constrained by external reasons to send it to the press in this form. Moreover I believe that I have solved in it a heretofore unsolved problem in the history of Greek philosophy.
The experts know that no preliminary studies that are even of the slightest use exist for the subject of this treatise. What Cicero and Plutarch have babbled has been babbled after them up to the present day. Gassendi, who freed Epicurus from the interdict which the Fathers of the Church and the whole Middle Ages, the period of realised unreason, had placed upon him, presents in his expositions  only one interesting element. He seeks to accommodate his Catholic conscience to his pagan knowledge and Epicurus to the Church, which certainly was wasted effort. It is as though one wanted to throw the habit of a Christian nun over the bright and flourishing body of the Greek Lais. It is rather that Gassendi learns philosophy from Epicurus than that he could teach us about Epicurus' philosophy.
This treatise is to be regarded only as the preliminary to a larger work in which I shall present in detail the cycle of Epicurean, Stoic and Sceptic philosophy in their relation to the whole of Greek speculation.  The shortcomings of this treatise, in form and the like, will be eliminated in that later work.
To be sure, Hegel has on the whole correctly defined the general aspects of the above-mentioned systems. But in the admirably great and bold plan of his history of philosophy, from which alone the history of philosophy can in general be dated, it was impossible, on the one hand, to go into detail, and on the other hand, the giant thinker was hindered by his view of what he called speculative thought par excellence from recognising in these systems their great importance for the history of Greek philosophy and for the Greek mind in general. These systems are the key to the true history of Greek philosophy. A more profound indication of their connection with Greek life can be found in the essay of my friend Köppen, Friedrich der Grosse und seine Widersacher. 
If a critique of Plutarch's polemic against Epicurus' theology has been added as an appendix, this is because this polemic is by no means isolated, but rather representative of an espèce, [species - Ed.] in that it most strikingly presents in itself the relation of the theologising intellect to philosophy.
The critique does not touch, among other things, on the general falsity of Plutarch's standpoint when he brings philosophy before the forum of religion. In this respect it will be enough to cite, in place of all argument, a passage from David Hume:
“... 'Tis certainly a kind of indignity to philosophy, whose sovereign authority ought everywhere to be acknowledged, to oblige her on every occasion to make apologies for her conclusions which may be offended at her. This puts one in mind of a king arraign'd for high treason against his subjects.” 
Philosophy, as long as a drop of blood shall pulse in its world-subduing and absolutely free heart, will never grow tired of answering its adversaries with the cry of Epicurus:
Not the man who denies the gods worshipped by the multitude, but he who affirms of the gods what the multitude believes about them, is truly impious.
Philosophy makes no secret of it. The confession of Prometheus:
In simple words, I hate the pack of gods
[Aeschylus, Prometheus Bound]
is its own confession, its own aphorism against all heavenly and earthly gods who do not acknowledge human self-consciousness as the highest divinity. It will have none other beside.
But to those poor March hares who rejoice over the apparently worsened civil position of philosophy, it responds again, as Prometheus replied to the servant of the gods, Hermes:
Be sure of this, I would not change my state
Of evil fortune for your servitude.
Better to be the servant of this rock
Than to be faithful boy to Father Zeus.
Prometheus is the most eminent saint and martyr in the philosophical calendar.
Berlin, March 1841
Chapter 1: Subject of the Treatise