¹ Pure Reason (Müller tr.), p. 515. Reason prescribes “to the understanding the rule of its complete application” (p. 463). It “frees, it may be, the concept of the understanding of the inevitable limitation of a possible experience” (p. 330).

“All our knowledge begins with the senses, proceeds thence to the understanding, and ends with reason. There is nothing higher than reason, for working up the material of intuition, and comprehending it under the highest unity of thought” (p. 242).

All future quotations from the Die Kritik der reinen Vernunft will be made from Müller's revised translation.

² “The supposition, therefore, which reason makes of a Supreme Being as the highest cause, is relative only, devised for the sake of the systematical unity in the world of sense, and a mere Something in the idea, while we have no concept of what it may be by itself” (p. 545).

“The ideal of the Supreme Being is … nothing but a regulative principle of reason, which obliges us to consider all connection in the world as if it arose from an all-sufficient necessary cause, in order to found on it the rule of a systematical unity necessary according to general laws for the explanation of the world” (p. 498).

“We have not the slightest ground to admit absolutely the object of that idea (to suppose it in itself)” (p. 550).

No experience can ever be adequate to “an extension of our knowledge beyond all limits of experience, till it reaches the existence of a Being which is to correspond to our pure idea” (p. 513).

“The concept of an absolutely necessary Being is a concept of pure reason, that is, a mere idea, the objective reality of which is by no means proved by the fact that reason requires it” (p. 477).

³ Prolegomena (E. B. Bax tr.), p. 36.

⁴ Kant's Critique of Practical Reason and other Works on the Theory of Ethics, Translated by T. K. Abbott, B.D., p. 260. All citations hereafter from Kant's ethical works will be made from this translation.

⁵ “In no way whatsoever can we know anything of the nature of our soul, so far as the possibility of its separate existence is concerned,” etc. (Pure Reason, p. 801). “We know ourself as a phenomenon only, and not as it is by itself” (p. 761). “I have no knowledge of myself as I am, but only as I appear to myself” (pp. 761, 762).

⁶ The Truth of the Christian Religion (Ferries tr.), II, p. 289.

⁷ “Virtue and happiness together constitute the possession of the summum bonum in a person, and the distribution of happiness in exact proportion to morality (which is the worth of the person, and his worthiness to be happy) constitutes the summum bonum of a possible world; hence this summum bonum expresses the whole, the perfect good, in which, however, virtue as the condition is always the supreme good, since it has no condition above it; whereas happiness, while it is pleasant to the possessor of it, is not of itself absolutely and in all respects good, but always pre-supposes morally right behaviour as its condition” (Prac. Reason, pp. 206, 207). “Morality is the supreme good (as the first condition of the summum bonum), while happiness constitutes its second element, but only in such a way that it is the morally conditioned, but necessary consequence of the former” (p. 215).

⁸ “The acting rational being in the world is not the cause of the world and of nature itself. There is not the least ground, therefore, in the moral law for a necessary connexion between morality and proportionate happiness in a being that belongs to the world as part of it and therefore dependent on it, and which for that reason cannot by his will be a cause of this nature, nor by his own power make it thoroughly harmonise, as far as his happiness is concerned, with his practical principles” (Prac. Reason, p. 221).

⁹ “It was seen to be a duty for us to promote the summum bonum; consequently it is not merely allowable but it is a necessity connected with duty as a requisite, that we should pre-suppose the possibility of this summum bonum, and as this is possible only on condition of the existence of God, it inseparably connects the supposition of this with duty; that is, it is morally necessary to assume the existence of God” (p. 222).

“It is a duty to realize the summum bonum to the utmost of our power, therefore it must be possible, consequently it is unavoidable for every rational being in the world to assume what is necessary for its objective possibility. The assumption is as necessary as the moral law, in connexion with which alone it is valid” (p. 242).

“In a mere course of nature in the world an accurate correspondence between happiness and moral worth is not to be expected, and must be regarded as impossible, and therefore the possibility of the summum bonum cannot be admitted from this side except on the supposition of a moral Author of the world” (p. 243).

¹⁰ “What man is or ought to be in a moral sense he must make or must have made himself.” “Duty commands nothing that is not practicable to us” (Theory of Religion (Abbott), p. 352 and p. 356).

¹¹ It is not meant that “it is necessary to suppose the existence of God as a basis of all obligation in general (for this rests, as has been sufficiently proved, simply on the autonomy of reason itself)” (Prac. Reason, p. 222).

Autonomy of the will “is the supreme principle of morality” (p. 59).

“Ethical legislation cannot be external (not even that of a divine will)” (p. 275).

Kant is expressly opposed to introducing “an external arbitrary legislation of a Supreme Being in place of an internal necessary legislation of Reason” (Critique of Judgement (Bernard tr.), p. 394). He says further: “Laws which Reason itself does not give and whose observance it does not bring about as a pure practical faculty, cannot be moral” (p. 428).

¹² “The word ‘belief’ refers only to the guidance which an idea gives me, and to its subjective influence on the conduct of my reason, which makes me hold it fast, though I may not be able to give an account of it from a speculative point of view” (Pure Reason, p. 663).