Kant was enlightened by Hume’s theory of cause and effect. Hume and Kant agreed and disagreed to many concepts regarding metaphysics. Hume was accustomed to believe in necessary connection. “Humean doubt” is the belief that you can not know or trust that the future will resemble the past. In contrast Kant believed empirical knowledge is never necessary and universal however cause is necessary and universal. He believed that things were known necessarily and the cause of something was beyond experience and could not be known. Kant disagrees with Hume’s idea of cause not coming from experience.

For Hume the knowledge of cause and effect is empirical, we develop this relation from experience, this is because we see the constant conjunction between two events, however we can not understand the connection between the events. Because of this “ It is wholly impossible for reason to think such conjunction a priori from concepts. For this conjunction contains necessity; but it is quite impossible to see how, because something is , something else mush also necessarily be, and how therefore the concept of such an a priori connection can be introduced( Prolegomena,4:258, p.65). This suggests that we do not have understanding of the necessity of the connection that occurs between cause and effect. However we only have subjective, and experimental information about their conjunction. First , I will describe The judgements of perception and judgements of experience that both philosophers cover and how Hume develops his scepticism . Then I will illustrate “Humean doubt” that Kant addresses and explain how he disposes of it, Second I will clarify if Kant is correct to characterize Hume’s position as one of doubt, Lastly , I will conclude all how both philosophers related to one another in relation to the“Humean doubt“.

The judgements of perception is subjective , meaning its everything internally sensed, heard and seen. It has no expectation for inter-subject agreement. The judgements of experiences are objective, they have necessity and universality . Hume believed in judgements of perception while Kant believed in Judgements of experience. Judgements of experience describes the cause of the effect. While Judgements of perception is the perceiving and feeling yet there is no causal inference made. Synthetic a prior is everything that happens has a cause, it is a pure concept of understanding related to cause, this concept also precedes empirical cognition of nature and makes the cognition of lawfully determined objects possible (§26,p113).

Hume categorizes between two kinds of scepticism: consequent and antecedent skepticism. Most important, antecedent Skepticism, consists of forming opinions, he describes it as being custom and habit of human nature , where reason breaks down judgments by doubt. Hume’s Skepticism is based on uniformity and laws of nature based on past experience. He describes naturalism as the science of human nature . These laws of nature of experience are not universal . Hume believes that cause is a concept of necessary connection with no justification by reason. Kant describes “the essential limitation of the concepts in these principles is therefore: that all things stand necessarily a priori under the said conditions only as objects of experience”( Prolegomena, 4: 309,p.114) . In general, experience is what allows for the constant conjunction of events to occur, meaning experience of the events depend upon intrinsic features so that they can be seen happening one after another. Therefore, Kant agrees that we as humans can not find the cause and effect in our experience. He disagrees with Hume’s theory if of human nature that is derived from “custom or habit, For wherever the repetitions o f any particular act or operation produces a propensity to renew the same act or operation, without being impelled by any reasoning or process of understanding.(EHU,para.5.p.121).

Hume claimed that we can never understand the cause and effect relationships a priori. Therefore ,causality does not have an objective necessity coming from insight, only a subjective necessity that arose based on custom. This is explained when he says “The imagination, having by experience brought certain representations under the law of association, passes off a subjective necessity arising out of this, namely custom, for an objective necessity from insight”(Prolegomena, 4: 258,p.65). A priori knowledge is the highest of knowledge. It allows for our prior senses of experience and perceptions to guide us. Although, it is a necessary knowledge integrated by our thoughts, it does not need to rely on anything empirically.
“Humean doubt” is David Hume’s doubt about causality . Causality being the necessary relationship between one event and another event which is the direct consequence of the first. He suggests that reason and experience can not connect things in the world and explain “ that every event has a cause.” He states, “that we can in no way have insight by reason into the possibility of causality, i.e. of the relation of the existence of a thing to the existence of something else which is posited necessary by the first” (4: 311,p.115). Hume concludes that we have no logical knowledge of cause and effect. In the end the idea of causation is convincing by the custom and habit of seeing events followed after others. This is explained in the prolegomena when it states “ Nonetheless I am far from holding that these concepts are merely taken from experience and that the necessity which is represented in them is fictitious and mere illusion imposed on us by long habit”(4:311,p.115-116). Kant goes about in his refusal of Hume’s skepticism by showing that we do have an a priori and necessary knowledge of causality and we can have a priori knowledge larger then what Hume suggested .

Kant responded to Hume’s skepticism and disposes of it by maintaining cause as synthetic conditioned idea that we create a priori to all experience. Kant agrees with Hume views of knowledge of cause is beyond experience. However believing that causation is an a prior to experience concept applied to two realms known as are phenomena , this is understanding that comes from experiences, also known as appearances, and noumena which are things in themselves that are comprised of reality. “Besides the beings of the senses or appearances (phenomena) which constitute the world of the senses, there were special beings of the understanding (noumena) , which were supposed to constitute a world of the understanding “(4:315,p.119). Our synthetic a priori judgments are derived from phenomena because humans can only know the appearance of objects that our sense perception and understanding presents us. The noumena is what we experience, it allows us to justify in imposing the conjunction of concepts to the objects of knowledge. Hume believed that all knowledge starts and rises from experience. In contrast to Kant’s belief that all knowledge starts but does not rise from experience including space and time. A priori element in our knowledge is prior to experience in the form of a cognitive disposition of the mind and it is in depended from any specific piece of experience.

The pure a priori concept of understanding includes pure concepts and insight that allows us to conclude the appearances. Kant believed that pure intuitions and concepts the a priori knowledge can not describe the nuemena”things in them selves”.
The pure concepts of understanding and intuitions of space and time, are a priori and therefore necessary, we desire to believe that we can receive knowledge further then what we find in experience. Moreover, they provide form (Phenomena ) and no substance (nuemena). Hume believed that all knowledge starts and rises from experience. In contrast to Kant’s belief that all knowledge starts but does not rise from experience including space and time.

The differences between Kant and Hume’s philosophies are described through Kant’s characterization of Hume’s position as one of doubt. Kant developed upon the idea that space and time, he described them as added immediately upon the first time of experience, However, Hume suggested that whatever we add to experiences only develops through many experiences when he says “..he has acquired more experience, and had lived so long in the world as to have observed similar objects or events to be constantly conjoined together“(EHU,para.4.p.120). Hume’s position allowed Kant to agree or disagree and expand upon his conclusions. The belief that one thing causes another believed by Hume when he stated“He would , indeed, immediately observe a continual succession of objects, and one event following another;…He would not , at first, by any reasoning , be able to reach the idea of cause and effect“(EHU,para.3.,p.120) was contradicted by Kant when he suggested that these psychological elements concerning experience and idea of cause are part of the cognitive structure. Hume characterizes “All belief of matter of fact or real existences is derived merely from some object, present tot the memory or senses, and a customary conjunction between that and some other object“(EHU, para.8.p.123). This explains the mind as conforming to the world in the form of constant conjunction , the mind develops this belief of a causal connection that when I do this , this will happen. However Kant suggests that this constant conjunction does not exist and that the objects of experience conform to the mind, allowing us to see appearances( Phenomena) and come in touch with conceptions(nuemena).

Metaphysics has gained in respect to Hume’s Criticism. Metaphysics is possible, as long as we have necessary, synthetic judgements priori knowledge . Moreover, Kant suggests the faculty of understanding as being the foundation, from that we develop concepts. From concepts comes the two law’s of nature Empirical as described by Hume, and Pure categories emphasized by Kant. Significantly many objects that are objective like causation, space and time, are dependent on knowledge. Hume’s scepticism in regards to reason, claims that custom, habit, and constant conjunctions are the source. In conclusion “Humean doubt“ is the relationship between one event and another event which ends in a consequence, it is the reason why one thing happens after another that contain necessity and universality. Hume concluded that one thing being the cause of another is what developed experience. Kant concluded that we have pure a prior knowledge that includes the understanding plus intuitions that results in experience.