LNAT Guides
LNAT Deductive Reasoning: How to Deduce Arguments in the LNAT 2023
Written by: Matt Amalfitano-Stroud
Deductive reasoning is an essential skill that everyone requires. It’s also not something that can necessarily be taught, but it’s certainly possible to sharpen your skills. When sitting the LNAT, you’re going to need to use your deductive reasoning skills in a very direct way, which is what we’re going to look at today! Let’s take the logical next step and get straight into it!
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WHAT IS DEDUCTIVE REASONING?
Deductive reasoning is practically built into our brains, but many don’t know what it actually means. Let’s find out now!
In its most basic form, deductive reasoning is a method of thought that begins with a broad concept and gradually narrows down to a specifically formed conclusion. It’s a system that is reliant on observations or evidence in order to direct an argument or idea towards a certain conclusion. In the end, the conclusion reached should answer a question, provide a truthful statement or achieve a goal of some variety.
Let’s take a look at look at deductive reasoning in action:
All Oxford Law Students have to complete the LNAT in their application.
Thomas is currently studying Law at Oxford.
Therefore Thomas has completed the LNAT.
This is an incredibly basic example, taking just three steps to reach a specific conclusion. The journey from an initial statement to the conclusion can go through many layers, all building upon the overall argument that is being made until a final conclusion is reached. The important thing to bear in mind is that all statements and ideas being presented are definitively truthful.
Exams.Ninja Tip
It can be extremely tempting to include assumptions and generalisations within the deductive reasoning process sometimes. You may have the perfect argument that’s dependent on just one small thing that isn’t definitively proven true but could logically be assumed. However, the inclusion of unproven facts is the point where deductive reasoning breaks down and becomes inductive reasoning (more on that here). In a situation that requires precision in your logic (such as a legal setting), any lapses in reasoning could easily negate your argument.
There are three different ways to present a deductive argument, let’s take a look at them:
Syllogism
This is the most simplistic way to develop two factual statements into a conclusion. The basic layout of this would be “if A = B and B = C, then A = C”, where A = B and B = C would be premises and A = C would be a conclusion.
Computers are electronic, electronics need a power source to function, so computers need a power source to function.
Modus Ponens
Here, a deduction will take the form of a conditional statement (a hypothesis and conclusion). Additional clauses are added to this initial statement to form a factual conclusion.
Nintendo only make games for their own consoles. Nintendo has just made a new game, so it must only be releasing on Nintendo consoles.
Modus Tollens
The antithesis of Modus Ponens, Modus Tollens follows the same overall format. However, the intention here is to refute a statement rather than affirm it. Basically, you’re trying to disprove a claim.
Alex is making orange paint. You can mix red and yellow together to make orange. Alex mixes red and blue together, so they will not make orange.
In real-life scenarios, these forms of deduction are going to be much less clear cut, with large numbers of relevant factors at play and the potential to mix proven facts with generalised statements and assumptions. What would these real-life scenarios be though?
Uses of Deductive Reasoning
Law
The most important use for deductive reasoning for us currently is its use in the legal field. Entering the legal profession requires you to constantly infer beneficial arguments based on available evidence and facts. Well trained legal professionals will be able to defend themselves from scrutiny by ensuring every statement can be traced to an available piece of evidence. While assumptions and inductive logic are certainly acceptable in some scenarios, it is essential to base a legal case on arguments deduced from indisputable evidence.
Investigations
Outside of court, deduction is also key to solving crimes, as we have seen from the many famous fictional detectives! Evidence could be deduced from anything that can link to an action or behaviour which may be considered relevant, so deductive reasoning is required to make those links.
Journalism
Typically, this applies more to opinion and argumentative pieces. When writing a piece designed to convince or allow for the understanding of an opinion, it’s vital that evidence is included in order to provide credibility to any claims made. This is the area of deductive reasoning that you’re going to need to understand the most when tackling the LNAT, as you’re going to have to both analyse and write arguments in a well-rounded manner.
Scientific Research
Deductive reasoning is often used within the scientific fields when performing experiments. Where inductive reasoning could be used before an experiment to theorise an outcome, deductive reasoning will need to be used once evidence is gathered in order to provide a conclusion that accurately reflects the outcome.
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DEDUCING ARGUMENTS IN LNAT SECTION A
With the general concepts of logical deduction in mind, it’s time to see how we can apply this to the LNAT!
As you should know by now, Section A of the LNAT is made up of multiple-choice questions relating to a series of short passages. These passages cover a wide and random selection of topics, so it’s not your understanding of the content itself that you’re being tested on; it’s your reading and reasoning abilities.
The questions in the LNAT will ask you a variety of questions about the text, usually asking you to identify a specific element of the writing or the context behind the writing (e.g. the author). The types of questions which typically require deduction skills are Argument and Analysis Questions, meaning they relate to the writing techniques the author has used more so than the content. These could range from finding the assumption in a paragraph to identifying the major point of the whole passage.
Your method of deductive reasoning will be somewhat different to typical cases, as you’ll be working backwards from a series of potential conclusions (the answers). Your job from here will then be to search the text for statements or concepts which could support a given conclusion. There are a few ways you can simplify the process of looking for these:
LNAT Deductive Reasoning Tips
- Read the question thoroughly – it’s common for LNAT questions to specify where in a passage you should be looking for an answer (e.g. “In the third paragraph…”).
- Skim through the text and highlight words that are relevant to the question. You’ll find what you’re looking for much quicker than reading everything fully.
- Try to present any relevant statements in a Syllogism format alongside the answer. If the conclusion makes sense, then that could very well be the answer.
- Eliminate as many answers as possible before deciding on your answer. Conclusions that don’t match up with the statements the author has provided can go in the bin to narrow your choice down!
One thing to bear in mind is that LNAT passages are sometimes opinion pieces, in which the author may not be basing their argument on indisputable facts. This of course would not count as deductive reasoning on their part, but your answer is simply focused on what has been written, not the actual context of the subject that is being discussed. Using statements that feature in the passage is definitively true in the sense that they are what the author has said. In the LNAT, this is all that actually matters.
This is a tricky topic to properly revise, but it’s definitely something that should be included within your preparation plan. The best way to properly explain this is through a worked example, so let’s have a look at one!
LNAT Practice Question: Colonialism
Most of the colonists who lived along the American seaboard in 1750 were the descendants of immigrants who had arrived a century before; after the first settlements, there had been much less fresh immigration than many latter-day writers have assumed. According to Prescott F. Hall, ‘the population of New England… at the date of the Revolutionary War… was produced out of an immigration of about 20,000 persons who arrived before 1640’, and we have Franklin’s authority for the statement that the total population of the colonies in 1751, then about 1,000,000, had been produced from an original immigration of less than 80,000.
Even at that early day, indeed, the colonists had begun to feel that they were distinctly separated, in culture and customs, from the mother-country and there were signs of the rise of a new native aristocracy, entirely distinct from the older aristocracy of the royal governors’ courts. The enormous difficulties of communication with England helped to foster this sense of separation.
The round trip across the ocean occupied the better part of a year, and was hazardous and expensive; a colonist who had made it was a marked man—as Hawthorne said, ‘the petit maître of the colonies’. Nor was there any very extensive exchange of ideas, as most of the books read in the colonies came from England. The great majority of the colonists, down to the middle of the century, seem to have read little save the Bible and biblical commentaries. In the native literature of the time, one seldom comes upon any reference to the English authors who were glorifying the period of the Restoration and the reign of Anne. ‘No allusion to Shakespeare’, says Bliss Perry, ‘has been discovered in the colonial literature of the seventeenth century, and scarcely an allusion to the Puritan poet Milton’. Benjamin Franklin’s brother, James, had a copy of Shakespeare at the New England Courant office in Boston, but Benjamin himself seems to have made little use of it, for there is not a single quotation from or mention of the bard in all his voluminous works. ‘The Harvard College Library in 1723’, says Perry, ‘had nothing of Addison, Steele, Bolingbroke, Dryden, Pope, and Swift, and had only recently obtained copies of Milton and Shakespeare… Franklin reprinted ‘Pamela’ and his Library Company of Philadelphia had two copies of ‘Paradise Lost’ for circulation in 1741, but there had been no copy of that work in the great library of Cotton Mather’.
Which of the following statements is supported by the above passage?
A) According to Hall, America’s population at the date of the Revolutionary War could be entirely traced back to 20,000 immigrants
B) The population in the 1751 colonies was over ten times the original immigration that moved there
C) According to Hall, in 1751, the population in the American colonies was one million
D) According to Hall, 80,000 people led to a population of 1,000,000
E) Most of the population on the American seaboard immigrated there
The correct answer is B.
Hall only makes a claim for New England, not the entirety of America, being the descendants of 20,000 immigrants. The ‘one million’ figure comes from Franklin, not Hall. Less than 80,000 (‘under’ 80,000) people led to the population boom of one million.
Let’s look at this as a deductive argument:
The total population in 1751 was stated to be 1,000,000.
The original population was stated to be less than 80,000.
Therefore, the 1951 population is 10x larger than the original.
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DEDUCTIVE REASONING IN YOUR LNAT SECTION B ESSAY
Identifying conclusions in an author’s work is one thing, it’s a whole other to develop and write the arguments yourself using your own logical deduction! So let’s explore what you’re going to want to do when writing your LNAT Section B Essay.
Just to recap, your Section B essay will be answering one of three questions targeting a variety of topics. You have a maximum of 750 words to write it, so you aren’t going to discuss a very large amount of topics or statements. Your time is also limited, so you may not be able to plan out things as much as you like.
How does Deductive Reasoning play into this?
Simply put, you’re going to deduce your conclusion based on your own knowledge of the topic. It’s fine to enter the planning stage of your essay with an opinion you want to express, but the whole point of the essay is to express this opinion in an understandable and logical manner. Basically, you’re going to have to back yourself up!
Assumptions and generalisations can only get you so far in an essay like this. In some cases, they may not be appropriate at all. Providing proven evidence is another story, however, and presenting said evidence as a deductive argument will leave little room for misinterpretation of your work.
Take this LNAT question as an example:
Does it matter if some species of plants or animals die out?
You’ll likely have an opinion on this one way or another (bearing in mind that it’s recommended you pick a side rather than sit on the fence). Let’s say that we believe it does matter if some species die out. What would be our major argument in favour of our case here?
All ecosystems are finely tuned and reliant on the organisms that live in them. This is known as the food chain.
Disruption to any part of the food chain will have an effect on every organism above it, which will typically end at human consumption of some form.
Therefore, the extinction of an animal or plant does matter as it has a negative impact on the natural food chain and thus, humanity’s food supply.
This is the skeleton of an effective LNAT essay, as it covers the two major statements that define the argument and then explain how they answer the question. This stage of the essay is simply about justifying your general answer with logical deduction.
From here, you will need to discuss the evidence behind these statements, which will require more deductive reasoning. You won’t be able to go too in-depth with it due to restrictions of the exam, but providing one or two points to back up your claims is essential for the credibility of your essay.
Keep in mind that you may have to rely on generalisation when writing here, as you’re not going to have actual references to back up your claims. The LNAT is typically marked on the assumption that the evidence provided is truthful though, so the actual marks will come from how effectively you’ve presented your evidence and linked it to your argument.
Deductive vs Inductive Reasoning
This is an area that will likely catch people out. Let’s look at the actual definitions for each of these terms to define the difference:
Deductive Reasoning – a method of drawing conclusions by going from the general to the specific.
Inductive Reasoning – a method of drawing conclusions by going from the specific to the general.
So they’re essentially opposites of each other. But how would you use an inductive argument?
If we were to make the deductive argument that…
“I found a red ball in a box, all of the balls in the box are red so the next ball I pick will be red”
…then an inductive argument would then be…
“I pick out two red balls from a box, so all of the balls must be red”.
In this example, the deductive argument is, of course, more sound (provided the statement of “all the balls are red” is true), whereas the inductive argument reaches its conclusion on an insubstantial amount of evidence. This is a very simplified example though and you may find that inductive arguments sometimes work in your favour if the logic behind your case is sensible enough to allow for an assumption like this. Generally speaking though, it’s best to speak with certainty by deducing actual evidence to support your claims.
Here are a few extra tips to help you through your Section B essay:
Time
Time is not your friend in this part of the LNAT, so you may try to rush the planning phase of the essay. Don’t do this, as you’ll be writing without direction which will eat up more time than you’ll save by skipping the planning phase. This is your chance to decide what your argument actually is!
Arguments
You’ll hopefully be going into this question with an idea of what your argument is. The next step is to determine what points you’re going to make to explain your argument. You should try to phrase your points as a direct answer to the question in order to see if they’re actually relevant. If you can’t turn your point into an effective one-sentence answer, then it probably isn’t the right thing to discuss.
Be Blunt
Although your word count is limited, you should take any steps necessary to ensure your point has been fully explained. Being unambiguous with your answer will greatly reduce the chances of scrutiny and misinterpretation, so if you feel there’s a gap in the explanation, fill it!
Conclusions
Always remember to conclude your essay with the actual answer to the question. The main content of your essay should always link back to the question, but the conclusion is your chance to definitively give an answer to what has been asked, as well as summarising your justification for said answer.
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LNAT PRACTICE QUESTIONS
Here are three LNAT passages with corresponding questions. Use your deductive reasoning skills to solve the answer, or check the worked solutions if you’re not sure.
LNAT Passage 1: Online Courts
There are two main ways to resolve a private dispute concerning a question of law. Firstly, you can come to a private settlement with the person you disagree with – this can either (i) just be between the two sides of the case or (ii) involve a third party as a mediator. Alternatively, if that does not work, you can sue the other person and seek redress from the courts. It is well known, though, that the court system in the UK is expensive, inefficient, and not suited to the needs of the ordinary person.
Let us say, for example, that you are having an electrician complete some wiring in your house at a price of £300. You pay the electrician and he leaves, but it then transpires that he completed the task erroneously and you want your money back. How do you go about getting it back? Would you go to court? Legal fees include the court fee of £35 for each side in the case and any legal advice from a solicitor would cost approximately £200 per hour. It must be noted that there is a well-established principle that the losing side in a civil case always pays the winning side’s legal costs. However, in the event that you do not win the case, you could potentially lose even more money from having to pay the winning side’s (the electrician’s) legal costs.
The cost is disproportionately high here in relation to the value of the claim and herein lies a flaw in the justice system. The high cost limits access to justice. The existing court process takes too long, involves too much paperwork and unnecessarily involves the use of expensive lawyers. Lord Dyson, a leading judge in the Court of Appeal (the second highest court in the UK), echoed these comments. Crucially, there are ways to make the system more efficient and the best way is to introduce an online court.
Firstly, we must accept the truth: lawyers are not always needed for small-time disputes. We can look to eBay for inspiration. eBay is a well-renowned online auction site where private individuals can sell goods to other individuals. It is not always smooth sailing, however, and frequently disputes arise (for example, when a damaged defective item is sold). When disagreements arise, the seller and buyer are encouraged to negotiate online. If negotiation fails, eBay offers an online resolution service whereby an eBay official decides on the case and makes a binding decision. This is without lawyers and not even any face-to-face interaction with the eBay official. For simple matters, it would be unnecessary and inefficient to hire a lawyer to complete the task. Crucially, this means much lower costs than in a courtroom.
This system should be used by the justice system for small claims. There should be an online mediation system to allow each side to negotiate in an online discussion area.
Anyone watching the ITV hit television show, Judge Rinder, would realise that small-time claims do not require a lawyer. The setting for the show resembles a courtroom where real small-time disputes are heard before a ‘judge’ who mediates between each side. The ‘judge’ then makes a decision that binds each side. There are no lawyers and each person represents him or herself. While there are a wealth of differences between the TV show and actual court proceedings, it does show that lawyers are not always needed to resolve disputes.
Accordingly, the Government should go one step further and establish an online court to resolve small-time legal disputes. This would involve real judges from the judiciary deciding cases online. They would review the documentary evidence submitted online by the parties and, if necessary, conduct a hearing via video link. While it would cost a lot to set up the online system, it would, in the long run, result in significant cost efficiencies both to the Government and to the users of the online court.
LNAT Practice Question 1
Assume that you and the electrician go to court. You each take 1 hour of legal advice from a solicitor. How much are the total legal fees for the losing side in the case?
A) £35
B) £200
C) £235
D) £300
E) £470
The correct answer is E.
This is an unusual question for the LNAT, but it’s one that necessitates being able to deduce the correct information from the passage. 1 hour of legal advice is £200 and the court fee for each is £35. Therefore, the cost for each side is £235. Therefore, the cost for both sides together is £470. As the passage stated that the losing side pays the winning side’s costs (as well as their own), the losing side would have to pay a total of £470.
LNAT Passage 2: Prisons
Prisons in the UK are failing. The reality is that the use of imprisonment is less a reflection of crime rates than an outcome of a country’s political, economic and institutional conditions. Neo-liberal nations, including the USA and the UK, imprison at much higher rates than countries where there is a more egalitarian culture, with a larger welfare state. We are over-burdening the taxpayer by throwing people into prison and paying to keep them there, rather than allowing them to undertake rehabilitation schemes within the community.
There is little evidence that prisons are effective in terms of deterrence or reform at a general level, although certain programmes and certain individuals sometimes show positive effects. Despite the positive effects on the minority of prisoners, the high rates of re-offending overall are, according to Clarke, stark evidence of the failure of the system. Clarke told BBC Radio 4’s Today programme that the prison system was failing to deter a ‘criminal underclass’ who revert back to committing ‘more crime’ as soon as they come out of prison because underlying problems such as drug abuse and mental illness issues were not being tackled by the prison system. Another issue was the lack of support for those able to change their ways who were striving (unsuccessfully) to obtain some form of legal employment. The institution of prison has, in fact, been found to have an overall negative effect – destabilising family ties, disrupting employment opportunities on a long-term basis, stigmatising individuals and otherwise deskilling its population.
29% of the prison population are serving sentences of over 4 years but often such prisoners are not dangerous at all. Rather, they have committed lots of property-related offences. The public are not benefitted from keeping these people in prison. In relation to these types of prisoners, Clarke said ‘What has been happening is there has been a huge increase in the number of people in prison, which is not only bad value for money, but even more importantly, I do not think that is the right way to keep on protecting people… some of my critics think you should put more and more people in prison for longer and longer and longer. I personally do not think that is the best way of protecting society. It seems that a thoughtless Victorian-style ‘bang em’ up’ mentality has prevailed in the UK.’
Moreover, it goes without saying that prison is a truly bleak experience for many. This means that some prisoners who might be reformed on the outside become too miserable or depressed to engage with the programmes being offered to them in prison. In England and Wales in 1995, the Government introduced an incentives and earned privileges (IEP) scheme. Prisoners on ‘basic’ – the lowest tier of the IEP scheme – are subject to quite an austere regime. Their in-cell TV is removed, they have reduced opportunities for mixing with other prisoners and they are forced to wear prison uniform. Making people miserable is not the way to bring about reform. We can never hope to cultivate something positive from such negative conditions.
LNAT Practice Question 2
What can we infer from the fact that prison may destabilise family ties and disrupt employment opportunities?
A) Prison may actually make rehabilitation harder
B) Some people do well in prison
C) Prison makes rehabilitation easy
D) The public are benefitted by keeping lots of people in prison
E) Prisons always reduce social mobility
The correct answer is A.
For this question, we could actually use Modus Tollens to come to ur conclusion. The author states ‘prison has in fact been found to have an overall negative effect’, which rules out B, C and D which are all positive outcomes.
LNAT Passage 3: Star Wars
Star Wars has stormed back onto the box office, just 10 years after the last one. In 2012, Disney famously bought the rights to the Star Wars franchise from the original founder, George Lucas. With the intention of producing another trilogy, Disney released the first film, Star Wars: The Force Awakens, in December 2015 to the delight of fans.
A few suggested that the film was based too much on the old style, but they were few and far between. The majority of cinema goers pronounced the film a success on social media and it immediately received positive critical acclaim. You know you have created a successful film when hard-to-please and meticulous critics give it a good rating. The actors themselves received heaps of praise as two up-and-coming British actors came into stardom.
The film did not just achieve success on this front. As a result of being a box office hit, it has reached $2 billion in box office sales, one of only three films to have ever done so. According to analysts, the success does not stop there, though. Some suggest that merchandise sales will outstrip the takings from box office sales.
An important part of most successful films is the consumer products that go with them and Star Wars is no exception. Disney exploited the pre-existing goodwill that the first six Star Wars films built up and licensed and created a vast array of products – from toy action figures of the film’s characters to remote controlled droids. Significantly, Disney did not create all of these products themselves. They have licensed the Star Wars brand to other companies, who are allowed to use the Star Wars brand on their own goods. This has meant that other companies can use their expertise to produce Star Wars related goods which Disney could not produce. Significantly, in return for using the Star Wars brand, such companies pay Disney a license fee. For example, Electronic Arts, the game software developer was granted a license to produce Star Wars video games. In return, they paid Disney $225 million.
Disney picked an unorthodox time of year to release the Star Wars film but this was another inspired decision, both in terms of film screenings and consumer products. Given the Christmas period, where parents would have been wondering what gifts to buy their children, Disney gave them a clear answer. In releasing the Star Wars products a month before the film, Disney gave fans and, crucially, parents the opportunity to consider buying them for Christmas. Unlike most children’s films, many of today’s parents were teenagers at the time of the original Star Wars trilogy (in 1977 to 1983) and, thus, would have likely had a greater inclination towards purchasing the Star Wars goods. It is clear that this merchandising strategy played out well as Star Wars merchandise sales boosted profits in their consumer products section by 23%.
Paradoxically, it seems, Disney’s share price has gone down since the release of the film. It appears though that this is due to concerns about a different part of the Disney Company, such as its ESPN network.
LNAT Practice Question 3
Which of the following is definitely false based on the passage?
A) The film is not a British Film
B) The film was successful
C) The founder of Star Wars played a role in the new film
D) Disney licensed all their merchandise to other companies.
E) The film was not a success in the eyes of a few people
The correct answer is D.
This option is definitely false because the fifth paragraph explicitly states that Disney created products. It also said that Disney did not create all of the products themselves, thus implying that they created at least some of the products themselves and that others created some of the products.
We have plenty more practice questions in our free content, plus you can find over 350+ more in our LNAT Preparation Platform which you can access instantly right now!
With a better understanding of deductive reasoning, you’re now closer to becoming a well-rounded law student! Remember, this is an important part of everyday life and even more so in law. Legal professionals will often find themselves under immense amounts of pressure to develop and present arguments in incredibly high stakes scenarios. Once you get to grips with the fundamentals, your only challenge is going to be finding the evidence to work with!
There’s so much more to learn about the Law National Aptitude Test (LNAT), so why not start with our Definitive Guide to the LNAT to get to grips with the full exam format!
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