why John Locke was important

John Locke was born in 1632 in Wrington, a small village in southwestern England. His father, also named John, was a legal clerk and served with the Parliamentary forces in the English Civil War. His family was well-to-do, but not of particularly high social or economic standing. Locke spent his childhood in the West Country and as a teenager was sent to Westminster School in London.

Locke was successful at Westminster and earned a place at Christ Church, Oxford. He was to remain in Oxford from 1652 until 1667. Although he had little appreciation for the traditional scholastic philosophy he learned there, Locke was successful as a student and after completing his undergraduate degree he held a series of administrative and academic posts in the college. Some of Locke’s duties included instruction of undergraduates. One of his earliest substantive works, the Essays on the Law of Nature, was developed in the course of his teaching duties. Much of Locke’s intellectual effort and energy during his time at Oxford, especially during his later years there, was devoted to the study of medicine and natural philosophy (what we would now call science). Locke read widely in these fields, participated in various experiments, and became acquainted with Robert Boyle and many other notable natural philosophers. He also undertook the normal course of education and training to become a physician.

Locke left Oxford for London in 1667 where he became attached to the family of Anthony Ashley Cooper (then Lord Ashley, later the Earl of Shaftesbury). Locke may have played a number of roles in the household, mostly likely serving as tutor to Ashley’s son. In London, Locke continued to pursue his interests in medicine and natural philosophy. He formed a close working relationship with Thomas Sydenham, who later became one the most famous physicians of the age. He made a number of contacts within the newly formed Royal Society and became a member in 1668. He also acted as the personal physician to Lord Ashley. Indeed, on one occasion Locke participated in a very delicate surgical operation which Ashley credited with saving his life. Ashley was one of the most prominent English politicians at the time. Through his patronage Locke was able to hold a series of governmental posts. Most of his work related to policies in England’s American and Caribbean colonies. Most importantly, this was the period in Locke’s life when he began the project which would culminate in his most famous work, the Essay Concerning Human Understanding. The two earliest drafts of that work date from 1671. He was to continue work on this project intermittentlyfor nearly twenty years.

Locke travelled in France for several years starting in 1675. When he returned to England it was only to be for a few years. The political scene had changed greatly while Locke was away. Shaftesbury (as Ashley was now known) was out of favor and Locke’s association with him had become a liability. It was around this time that Locke composed his most famous political work, the Two Treatises Concerning Government. Although the Two Treatises would not be published until 1689 they show that he had already solidified his views on the nature and proper form of government. Following Shaftesbury’s death Locke fled to the Netherlands to escape political persecution. While there Locke travelled a great deal (sometimes for his own safety) and worked on two projects. First, he continued work on the Essay. Second, he wrote a work entitled Epistola de Tolerantia, which was published anonymously in 1689. Locke’s experiences in England, France, and the Netherlands convinced him that governments should be much more tolerant of religious diversity than was common at the time.

Following the Glorious Revolution of 1688-1689 Locke was able to return to England. He published both the Essay and the Two Treatises (the second anonymously) shortly after his return. He initially stayed in London but soon moved to the home of Francis and Damaris Masham in the small village of Oates, Essex. Damaris Masham, who was the daughter of a notable philosopher named Ralph Cudworth, had become acquainted with Locke several years before. The two formed a very close friendship which lasted until Locke’s death. During this period Locke kept busy working on politics, toleration, philosophy, economics, and educational theory.

Locke engaged in a number of controversies during his life, including a notable one with Jonas Proast over toleration. But Locke’s most famous and philosophically important controversy was with Edward Stillingfleet, the Bishop of Worcester. Stillingfleet, in addition to being a powerful political and theological figure, was an astute and forceful critic. The two men debated a number of the positions in the Essay in a series of published letters.

In his later years Locke devoted much of his attention to theology. His major work in this field was The Reasonableness of Christianity, published (again anonymously) in 1695. This work was controversial because Locke argued that many beliefs traditionally believed to be mandatory for Christians were unnecessary. Locke argued for a highly ecumenical form of Christianity. Closer to the time of his death Locke wrote a work on the Pauline Epistles. The work was unfinished, but published posthumously. A short work on miracles also dates from this time and was published posthumously.

Locke suffered from health problems for most of his adult life. In particular, he had respiratory ailments which were exacerbated by his visits to London where the air quality was very poor. His health took a turn for the worse in 1704 and he became increasingly debilitated. He died on 28 October 1704 while Damaris Masham was reading him the Psalms. He was buried at High Laver, near Oates. He wrote his own epitaph which was both humble and forthright.

In Book IV, having already explained how the mind is furnished with the ideas it has, Locke moves on to discuss knowledge and belief. A good place to start is with a quote from the beginning of Book IV: “Knowledge then seems to me to be nothing but the perception of the connexion and agreement, or disagreement and repugnancy of any of our Ideas. Where this Perception is, there is Knowledge, and where it is not, there, though we may fancy, guess, or believe, yet we always come short of Knowledge.” (4.2.2, 525). Locke spends the first part of Book IV clarifying and exploring this conception of knowledge. The second part focuses on how we should apportion belief in cases where we lack knowledge.

What does Locke mean by the “connection and agreement” and the “disagreement and repugnancy” of our ideas? Some examples might help. Bring to mind your idea of white and your idea of black. Locke thinks that upon doing this you will immediately perceive that they are different, they “disagree”. It is when you perceive this disagreement that you know the fact that white is not black. Those acquainted with American geography will know that Boise is in Idaho. On Locke’s account of knowledge, this means that they are able to perceive a certain connection that obtains between their idea of Idaho and their idea of Boise. Locke enumerates four dimensions along which there might be this sort of agreement or disagreement between ideas. First, we can perceive when two ideas are identical or non-identical. For example, knowing that sweetness is not bitterness consists in perceiving that the idea of sweetness is not identical to the idea of bitterness. Second, we can perceive relations that obtain between ideas. For example, knowing that 7 is greater than 3 consists in perceiving that there is a size relation of bigger and smaller between the two ideas. Third, we can perceive when our idea of a certain feature accompanies our idea of a certain thing. If I know that ice is cold this is because I perceive that my idea of cold always accompanies my idea of ice. Fourthly, we can perceive when existence agrees with any idea. I can have knowledge of this fourth kind when, for example, I perform the cogito and recognize the special relation between my idea of myself and my idea of existence. Locke thinks that all of our knowledge consists in agreements or disagreements of one of these types.

After detailing the types of relations between ideas which constitute knowledge Locke continues on to discuss three “degrees” of knowledge in 4.2. These degrees seem to consist in different ways of knowing something. The first degree Locke calls intuitive knowledge. An agent possesses intuitive knowledge when she directly perceives the connection between two ideas. This is the best kind of knowledge, as Locke says “Such kind of Truths, the Mind perceives at the first sight of the Ideas together, by bare Intuition, without the intervention of any other Idea; and this kind of knowledge is the clearest, and most certain, that humane Frailty is capable of.” (4.2.1, 531). The second degree of knowledge is called demonstrative. Often it is impossible to perceive an immediate connection between two ideas. For example, most of us are unable to tell that the three interior angles of a triangle are equal to two right angles simply by looking at them. But most of us, with the assistance of a mathematics teacher, can be made to see that they are equal by means of a geometric proof or demonstration. This is the model for demonstrative knowledge. Even if one is unable to directly perceive a relation between idea-X and idea-Y one might perceive a relation indirectly by means of idea-A and idea-B. This will be possible if the agent has intuitive knowledge of a connection between X and A, between A and B, and then between B and Y. Demonstrative knowledge consists, therefore, in a string of relations each of which is known intuitively.

The third degree of knowledge is called sensitive knowledge and has been the source of considerable debate and confusion among Locke commentators. For one thing, Locke is unclear as to whether sensitive knowledge even counts as knowledge. He writes that intuitive and demonstrative knowledge are, properly speaking, the only forms of knowledge, but that “There is, indeed, another Perception of the Mind…which going beyond bare probability, and yet not reaching perfectly to either of the foregoing degrees of certainty, passes under the name of Knowledge.” (4.2.14, 537). Sensitive knowledge has to do with the relationship between our ideas and the objects in the external world that produce them. Locke claims that we can be certain that when we perceive something, an orange, for example, there is an object in the external world which is responsible for these sensations. Part of Locke’s claim is that there is a serious qualitative difference between biting into an orange and remembering biting into an orange. There is something in the phenomenological experience of the former which assures us of a corresponding object in the external world.

Locke spends a fair amount of time in Book IV responding to worries that he is a skeptic or that his account of knowledge, with its emphasis on ideas, fails to be responsive to the external world. The general worry for Locke is fairly simple. By claiming that ideas are the only things humans have epistemic access to, and by claiming that knowledge relates only to our ideas, Locke seems to rule out the claim that we can ever know about the external world. Lockean agents are trapped behind a “veil of ideas.” Thus we cannot have any assurance that our ideas provide us with reliable information about the external world. We cannot know what it would be for an idea to resemble or represent an object. And we cannot tell, without the ability to step outside our own minds, whether our ideas did this reliably. This criticism has historically been thought to endanger Locke’s entire project. Gilbert Ryle’s memorable assessment is that “nearly every youthful student of philosophy both can and does in his second essay refute Locke’s entire Theory of Knowledge.” Recent scholarship has been much more charitable to Locke. But the central problem is still a pressing one.

Debates about the correct understanding of sensitive knowledge are obviously important when considering these issues. At first blush, the relation involved in sensitive knowledge seems to be a relation between an idea and a physical object in the world. But, if this reading is correct, then it becomes difficult to understand the many passages in which Locke insists that knowledge is a relation that holds only between ideas. Also relevant are debates about how to correctly understand Lockean ideas. Recall from above that although many understand ideas as mental objects, some understand them as mental acts. While most of the text seems to favor the first interpretation, it seems that the second interpretation has a significant advantage when responding to these skeptical worries. The reason is that the connection between ideas and external world objects is built right into the definition of an idea. An idea just is a perception of an external world object.

However the debates discussed in the previous paragraph are resolved, there is a consensus among commentators that Locke believes the scope of human understanding is very narrow. Humans are not capable of very much knowledge. Locke discusses this is 4.3, a chapter entitled “Extent of Humane Knowledge.” The fact that our knowledge is so limited should come as no surprise. We have already discussed the ways in which our ideas of substances are problematic. And we have just seen that we have no real understanding of the connection between our ideas and the objects that produce them.

The good news, however, is that while our knowledge might not be very extensive, it is sufficient for our needs. Locke’s memorable nautical metaphor holds that: “’Tis of great use to the Sailor to know the length of his Line, though he cannot with it fathom all the depths of the Ocean. ‘Tis well he knows, that it is long enough to reach the bottom, at such Places, as are necessary to direct his Voyage, and caution him against running upon Shoales, that may ruin him. Our Business here is not to know all things, but those which concern our Conduct.” (1.1.6, 46). Locke thinks we have enough knowledge to live comfortable lives on Earth, to realize that there is a God, to understand morality and behave appropriately, and to gain salvation. Our knowledge of morality, in particular, is very good. Locke even suggests that we might develop a demonstrable system of morality similar to Euclid’s demonstrable system of geometry. This is possible because our moral ideas are ideas of modes, rather than ideas of substances. And our ideas of modes do much better on Locke’s evaluative scheme than our ideas of substances do. Finally, while the limits to our knowledge might be disappointing, Locke notes that recognizing these limits is important and useful insofar as it will help us to better organize our intellectual inquiry. We will be saved from investigating questions which we could never know the answers to and can focus our efforts on areas where progress is possible.

One benefit of Locke’s somewhat bleak assessment of the scope of our knowledge was that it caused him to focus on an area which was underappreciated by many of his contemporaries. This was the arena of judgment or opinion, belief states which fall short of knowledge. Given that we have so little knowledge (that we can be certain of so little) the realm of probability becomes very important. Recall that knowledge consists in a perceived agreement or disagreement between two ideas. Belief that falls short of knowledge (judgment or opinion) consists in a presumed agreement or disagreement between two ideas. Consider an example: I am not entirely sure who the Prime Minister of Canada is, but I am somewhat confident it is Stephen Harper. Locke’s claim is that in judging that the Canadian PM is Stephen Harper I am acting as though a relation holds between the two ideas. I do not directly perceive a connection between my idea of Stephen Harper and my idea of the Canadian PM, but I presume that one exists.

After offering this account of what judgment is, Locke offers an analysis of how and why we form the opinions we do and offers some recommendations for forming our opinions responsibly. This includes a diagnosis of the errors people make in judging, a discussion of the different degrees of assent, and an interesting discussion of the epistemic value of testimony.