David Hume applies the central principle(s) of empiricism more consistently than Locke and Berkeley.
Hume explains that the associations that we make in our mind are habits, and this skeptic attitude helps us question to know if they are truths.
There is a similarity with all empiricist which is the use of the theory of ideas is used by all empiricist, yet some of them change some things.
Locke theory of ideas includes a god who in his point of view created the physical objects (which also have attributes and substance), by perception we can see the color of a thing this would create a simple impression which will lead to an idea, and a group of simple ideas would create a complex idea. For example you could observe an object and see that its color is red (simple idea creates an idea), then you could touch the object and feel that the shape is round, with these multiple ideas you can know that the object is a red ball (complex idea). this model follows what the empiricist believe. Yet there is a manner in which he fails; he does not explain where does the idea of substance comes from, since we can only have an experience the attributes with our senses. the question of where does the idea of substance come from if we cannot experience it and Locke mentions that there are no ideas that we are born with. Since there is no answer to this, it does not fit the base of empiricism which is experience based.
Hume theory of ideas is a bit different from Locke's its similar but it excludes god and a physical world. According to him he did not include god in his theory since it cannot provide a time when have a sensation like touching or hearing of god so this claim becomes nonsense.
Hume says that knowledge is about claims and analyze those claims to know if they are true real or nonsense. Hume developed a method called Hume Fork; for every single claim there is the possibility to be tested and know into which of the tree categories it belongs to. Those categories are Analytical which are claims that are independent of sense experience, they are necessary true. An example of Analytical claim is a "A priest does not have children"
Synthetic claims tell something of the world, most of them are based in experience of our senses, yet not all of them are not necessary true. An example of Synthetic claim is a "Sebastian is a priest"-(he might have married). Also some claims are nonsense since they are not based in any type of sensation. An example of nonsense claim is "god exists". Hume makes connections of the ideas based in time, space, resemblance, cause and effect. Since we have a tendency to group activities is a habit of