[1 of 6] Kant, Immanuel (1724-1804, Germany): primary subject "Philosophy, extracts" (search under Inner Life/Mind, Psyche, Soul, Spirit)": source "Critique of Pure Reason": detail "Part First, Section 2 “Of Time” [first edition]"
1. Time is not an empirical conception. For neither coexistence nor succession would be perceived by us, if the representation of time did not exist as a foundation a priori. Without this presupposition we could not represent to ourselves that things exist together at one and the same time, or at different times, that is, contemporaneously, or in succession.
 2. Time is a necessary representation, lying at the foundation of all our intuitions. With regard to phenomena in general, we cannot think away time from them, and represent them to ourselves as out of and unconnected with time, but we can quite well represent to ourselves time void of phenomena. Time is therefore given a priori. In it alone is all reality of phenomena possible. These may all be annihilated in thought, but time itself, as the universal condition of their possibility, cannot be so annulled.
 3. On this necessity a priori, is also founded the possibility of apodictic principles of the relations of time, or axioms of time in general, such as, “Time has only one dimension,” “Different times are not coexistent but successive” (as different spaces are not successive but coexistent). These principles cannot be derived from experience, for it would give neither strict universality, nor apodictic certainty. We should only be able to say, “so common experience teaches us,” but not it must be so. They are valid as rules, through which, in general, experience is possible; and they instruct us respecting experience, and not by means of it.
 [Alternate translation: 1. Time is not an empirical concept deduced from any experience, for neither coexistence nor succession would enter into our perception, if the representation of time were not given "a priori". Only when this representation "a priori" is given, can we imagine that certain things happen at the same time (simultaneously) or at different times (successively).
 2. Time is a necessary representation on which all intuitions depend. We cannot take away time from phenomena in general, though we can well take away phenomena out of time. Time therefore is given "a priori". In time alone is reality of phenomena possible. All phenomena may vanish, but time itself (as the general condition of their possibility) cannot be done away with.]

[2 of 6] Kant, Immanuel (1724-1804, Germany): primary subject "Philosophy, extracts" (search under Inner Life/Mind, Psyche, Soul, Spirit)": detail "‘Critique of Pure Reason: Second Section of the Transcendental Aesthetic’, part 5 ‘Transcendental Exposition of the Concept of Time’"
The concept of change, and with it the concept of motion (as change of place), is possible only through and in the representation of time; and that, if this representation were not intuitive (internal) a priori, no concept, whatever it be, could make us understand the possibility of a change.

[3 of 6] Kant, Immanuel (1724-1804, Germany): primary subject "Philosophy, extracts" (search under Inner Life/Mind, Psyche, Soul, Spirit)": source "Critique of Pure Reason": detail "Part First, Section 2 “Of Time”"
1. Time is not something which subsists of itself, or which inheres in things as an objective determination, and therefore remains, when abstraction is made of the subjective conditions of the intuition of things. For in the former case, it would be something real, yet without presenting to any power of perception any real object. In the latter case, as an order or determination inherent in things themselves, it could not be antecedent to things, as their condition, nor discerned or intuited by means of synthetical propositions a priori. But all this is quite possible when we regard time as merely the subjective condition under which all our intuitions take place. For in that case, this form of the inward intuition can be represented prior to the objects, and consequently a priori.
 2. Time is nothing else than the form of the internal sense, that is, of the intuitions of self and of our internal state. For time cannot be any determination of outward phenomena. It has to do neither with shape nor position; on the contrary, it determines the relation of representations in our internal state. And precisely because this internal intuition presents to us no shape or form, we endeavor to supply this want by analogies, and represent the course of time by a line progressing to infinity, the content of which constitutes a series which is only of one dimension; and we conclude from the properties of this line as to all the properties of time, with this single exception, that the parts of the line are coexistent, while those of time are successive. From this it is clear also that the representation of time is itself an intuition, because all its relations can be expressed in an internal intuition.
 3. Time is the formal condition a priori of all phenomena whatsoever. Space, as the pure form of external intuition, is limited as a condition a priori to external phenomena alone. On the other hand, because all representations, whether they have or have not external things for their objects, still in themselves, as determinations of the mind, belong to our internal state; and because this internal state is subject to the formal condition of the internal intuition, that is, to time—time is the condition a priori of all phenomena whatsoever—the immediate condition of all internal, and thereby the mediate condition all external phenomena. If I can say a priori, “all outward phenomena are in space, and determined a priori according to the relations of space,” I can also, from the principle of the internal sense, affirm universally, “all phenomena in general, that is, all objects of the senses, are in time, and stand necessarily in relations of time.”
 If we abstract our internal intuition of ourselves, and all external intuitions, possible only by virtue of this internal intuition, and presented to us by our faculty of representation, and consequently take objects as they are in themselves, then time is nothing. It is only of objective validity in regard to phenomena, because these are things which we regard as objects of our senses. It is no longer objective, if we make abstraction of the sensuousness of our intuition, in other words, of that mode of representation which is peculiar to us, and speaks of things in general. Time is therefore merely a subjective condition of our (human) intuition (which is always sensuous, that is, so far as we are affected by objects), and in itself, independently of the mind or subject, is nothing. Nevertheless, in respect of all phenomena, consequently of all things which come within the sphere of our experience, it is necessarily objective. We cannot say, “all things are in time,” because in this conception of things in general, we abstract and make no mention of any sort of intuition of things. But this is the proper condition under which time belongs to our representation of objects. If we add the condition to the conception, and say, “all things, as phenomena, that is, objects of sensuous intuition, are in time,” then the proposition has its sound objective validity and universality a priori.
 What we have now set forth teaches, therefore, the empirical reality of time; that is, its objective validity in reference to all objects which can ever be presented to our senses. And as our intuition is always sensuous, no object ever can be presented to us in experience, which does not come under the conditions of time. On the other hand, we deny to time all claim to absolute reality; that is, we deny that it, without having regard to the form of our sensuous intuition, absolutely inheres in things as a condition or property. Such properties as belong to objects as things in themselves, never can be presented to us through the medium of the senses. Herein consists, therefore, the transcendental ideality of time, according to which, if we abstract the subjective conditions of sensuous intuition, it is nothing, and cannot be reckoned as subsisting or inhering in objects as things in themselves, independently of its relation to our intuition. This ideality, like that of space, is not to be proved or illustrated by fallacious analogies with sensations, for this reason—that in such arguments or illustrations, we make the presupposition that the phenomenon, in which such and such predicates inhere, has objective reality, while in this case we can only find such an objective reality as is itself empirical, that is, regards the object as a mere phenomenon.

[4 of 6] Kant, Immanuel (1724-1804, Germany): primary subject "Philosophy, extracts" (search under Inner Life/Mind, Psyche, Soul, Spirit)": source "Prolegomena to Any Future Metaphysics": detail "‘Critique of Pure Reason’: The Transcendental Doctrine of the Elements, Second Part, ‘Axioms of Intuition’, 3: Analogies of Experience"
The three modes of time are persistence, succession, and simultaneous existence.

[5 of 6] Kant, Immanuel (1724-1804, Germany): primary subject "Philosophy, extracts" (search under Inner Life/Mind, Psyche, Soul, Spirit)": source "Critique of Pure Reason": detail "Part First, Section 2 “Of Time”"
Against this theory, which grants empirical reality to time, but denies to it absolute and transcendental reality, I have heard from intelligent men an objection so unanimously urged, that I conclude that it must naturally present itself to every reader to whom these considerations are novel. It runs thus: “Changes are real” (this the continual change in our own representations demonstrates, even though the existence of all external phenomena, together with their changes, is denied). Now, changes are only possible in time, and therefore time must be something real. But there is no difficulty in answering this. I grant the whole argument. Time, no doubt, is something real, that is, it is the real form of our Internal intuition. It therefore has subjective reality, in reference to our internal experience, that is, I have really the representation of time, and of my determinations therein. Time, therefore, is not to be regarded as an object, but as the mode of representation of myself as an object. But if I could intuit myself, or be intuited by another being, without this condition of sensibility, then those very determinations which we now represent to ourselves as changes, would present to us a knowledge in which the representation of time, and consequently of change, would not appear. The empirical reality of time, therefore, remains, as the condition of all our experience. But absolute reality, according to what has been said above, cannot be granted it. Time is nothing but the form of our internal intuition. If we take away from it the special condition of our sensibility, the conception of time also vanishes; and it inheres not in the objects themselves, but solely in the subject (or mind) which intuits them.
 But the reason why this objection is so unanimously brought against our doctrine of time, and that too by disputants who cannot start any intelligible arguments against the doctrine of the ideality of space, is this—they have no hope of demonstrating apodictically the absolute reality of space, because the doctrine of idealism is against them, according to which the reality of external objects is not capable of any strict proof. On the other hand, the reality of the object of our internal sense (that is, myself and my internal state) is clear immediately through consciousness. The former—external objects in space—might be a mere delusion, but the latter—the object of my internal perception—is undeniably real. They do not, however, reflect that both, without question of their reality as representations, belong only to the genus phenomenon, which has always two aspects, the one, the object considered as a thing in itself, without regard to the mode of intuiting it, and the nature of which remains for this very reason problematical, the other, the form of our intuition of the object, which must be sought not in the object as a thing in itself, but in the subject to which it appears—which form of intuition nevertheless belongs really and necessarily to the phenomenal object.

[6 of 6] Ouspensky, Pyotr D. (1878-1947, Russia): primary subject "Time" (search under Cosmology/Cosmology, Laws)": source "New Model of the Universe": detail "Chapter 3"
Time is not a condition of the existence of the universe, but only a condition of the perception of the world by our psychic apparatus, which imposes on the world conditions of time, since otherwise the psychic apparatus would be unable to conceive it.