4 Debates in Philosophy Everyone Should Know About

One of the best things about studying Philosophy is that it’s one of the world’s oldest fields of study. As long as humans have existed, we’ve been asking questions such as wondering where we come from, why we’re here, and whether any divine powers control our existence. Many of those questions haven’t been satisfactorily resolved – there are some we may never be able to satisfactorily resolve – but when you study Philosophy, you study this long history of discussion and argument, seeing how some ideas were discarded while new ones came to fruition, and you get to add your own thoughts to that process as well.
Philosophy can seem like the ultimate ivory-tower discipline, disconnected entirely from the real world. But that impression is misleading. From ethics to epistemology, Philosophy addresses ideas that have real-world concepts. Even when philosophical discussions themselves are abstract, the way we address them reflects and develops the ways in which we arrive at what we hold to be the truth.
In this article, we take a look at some of the key questions philosophers over time have sought to answer, and the ideas they came up with.

1.Is the world we live in actually real?

Image shows a woman using a virtual reality headset.
Philosophers have asked how we can be sure we’re not just experiencing an elaborate virtual reality scenario.

We are all aware of the ways in which our minds can play tricks on us so that what we perceive of the world around us contains errors – any optical illusion can demonstrate that. And if you’re colourblind, short-sighted or even have an unusually good sense of smell, you know that what you perceive of the world isn’t what everyone else is perceiving.
But underlying these differences is often the belief that there is a single objective reality that is simply interrupted by the errors in our own perception. People who are short-sighted don’t believe that the world really becomes out of focus a certain distance away from them; people with red/green colourblindness acknowledge that a distinction between those colours exists for everyone else.
It’s when you enter the realms of Philosophy that you encounter scepticism about the idea of an objective, external reality. One version of this idea was popularised by The Matrix – essentially, how can you be sure that the reality you experience is real, and not just simulated to you? How can you be confident that you aren’t just a brain in a jar? But philosophers don’t need to invent science-fiction universes to pose these questions. If the external world that you perceive isn’t real, it doesn’t necessarily need to be the case that there is another, real world being hidden from you. It may be that your consciousness and your perceptions are all that there is. And if that sounds ridiculous, think about how difficult it might be to prove otherwise.
Among philosophers, there are different schools of thought. Realists hold that there is such a thing as objective, external reality. Then there are assorted flavours of anti-realism. Idealism argues that reality was a product of our ideas; phenomenalism, that reality is a product of our perceptions and memories of previous perceptions.
And beyond this, there are debates about which aspects of what we perceive are real and which are not – for instance, some philosophers argue that the past, present and future are real, but that time is an illusion. Others argue that even if we can prove the universe as it is now is real, how can we guarantee that it was real five minutes ago, rather than being created afresh, with all records of the past created with it?
These questions then come to intersect with questions in Physics – for instance, quantum mechanics also challenges our ideas about how static and measurable the “real” world actually is. While Philosophy is typically placed alongside the humanities, it isn’t unusual for philosophers to work with the sciences as well to inform these debates further.

2. What is consciousness?

Image shows a neuron
Is our experience of consciousness just down to the firing and misfiring of neurons?

Just as philosophers debate whether the world is real beyond our consciousness, they also debate what consciousness itself can be said to be. We all share an intuition about what it is to be conscious, but defining that is much harder.
One debate is between dualism and materialism. Dualists hold that the conscious mind is separate in some sense from the body, which is how most people intuitively think about their mind – you think about thinking as a separate action, not as “I am thinking with my brain, which is in my head”. Monists hold that the conscious mind is entirely and exclusively the neural activity within our brains, and if it feels to us like a separate process, that is also our brains misleading us. Others still will argue that the mind is not separate from the body, but that there is a separate category of the soul.
Many of these questions are sharpened by comparisons with non-human animals and with machines. We can create a machine that can detect different colours and proceed accordingly (such as a self-driving car interpreting traffic signals) but can we make that machine conscious of that process in the way that we are conscious of the process?
That leads to the question of how we can tell whether any other being is conscious, other than ourselves. Philosopher John Searle proposed the Chinese room argument to demonstrate the problem. He imagines himself as an English speaker alone in a room, unable to speak Chinese, with a book containing a series of Chinese symbols that he is to output, along with the box of symbols. He can arrange the symbols in the order the book tells him to, but he can’t understand them. But if the same experiment were to happen in English, he could understand what he was saying. To the outside observer, though, the outputs of Chinese and of English look exactly the same – there is no way for the observer to know whether the man in the room understands them or not.
Searle used this to demonstrate the problem of consciousness within artificial intelligence – how can we tell if the machine is conscious, or if it has simply been programmed to simulate consciousness without any of the interior experience that we associate with consciousness? But you could raise the same question in relation to any being that alleges to be conscious. As we currently have no way for one person to experience what is happening within another’s mind, we can’t say for sure who is experiencing consciousness and who is merely processing external stimuli and responding to them in a way that simulates consciousness.

3. What system should we use to make moral decisions?

Image shows Lady Justice, holding the Scales of Justice.
The moral system we use has consequences in many areas, such as in the area of law and justice.

One of the biggest questions in Philosophy is the question of how we can separate right from wrong and work out what the moral path is in any given situation. A classic explainer of different moral systems is given through the “trolley problem”, which is as follows. A trolley is hurtling down a railway track, where some villainous person has tied five people to the rails. If the trolley hits them, they will die. Off in another direction, the villain has tied one person to the tracks. You’re standing next to the points – if you pull the lever you can redirect the careering trolley towards the single person, killing them but saving the other five. Is it right for you to do so?
There are other variations of the problem to test your instincts further. Let’s say the out-of-control trolley is still heading towards five people. You’re on a bridge with a very overweight man. If you push him off the bridge – towards his certain death – his weight will stop the trolley, saving the five people’s lives. Do you push him?
For many people, the instinctive answer to the first question is to pull the lever, but they couldn’t bring themselves to push the man, even though the number of lives lost and saved by their action is exactly the same. For others, neither pulling the lever nor pushing the man is acceptable, because they feel that the absolute rule against murder should be kept, even if circumstances where breaking it would involve saving a net number of lives. And some argue that what’s most important is saving the maximum possible number of lives, regardless of how that’s achieved.
Using different scenarios and thought experiments like the example above, philosophers test different moral principles to see if they still hold true for edge cases or whether they produce undesirable outcomes. For instance, utilitarianism – which holds that the right thing to do is whatever produces the greatest good for the greatest number – is vulnerable to extremes of number (where there are billions upon billions of people who are barely happy) or to extremes of happiness (where one being is capable of feeling extraordinary happiness, at the cost of all other beings who cannot generate as much happiness). Other moral systems can be challenged in similar ways.
It’s unlikely that we’ll ever work out one system that provides the right answer to every moral dilemma – or that we’ll be able to agree on it – but the process of deciding is valuable in its own right. These are, after all, not just abstract questions. Even the life-or-death questions are relevant to people from many different walks of life who have to decide which lives to prioritise, such as doctors, MPs, the emergency services, and even relatively new jobs such as programmers working on self-driving cars, and their decisions are informed by the deliberations of philosophers.

4. Is there such a thing as free will?

Image shows a man looking out over the wilderness, as if trying to decide which way to go.
Do we choose our paths for ourselves, or are they chosen for us?

An area where Philosophy intersects with other disciplines, particularly Psychology, is in asking whether or not human beings have free will. A basic definition of free will is being able to choose your own actions freely. For instance, all the moral decisions in the question above assume that we can actually make a choice between the different options, whether we ultimately choose the morally correct option or not.
From the perspective of neuroscience, it’s certainly arguable that we don’t make that choice freely. We are all subject to our own brain chemistry, which changes the way we make decisions, from minor changes such as feeling more amenable to other people’s suggestions after you’ve had a cup of coffee, to major ones such as the influence of depression on decision-making. And these things in turn – from our susceptibility to caffeine to our likelihood of mental illness – is affected by our environment, our upbringing, and above all by our genes. We might think that we’re making the decision freely, but it’s arguably nothing of the sort.
But one of the many roles of Philosophy is to fill the spaces beyond scientific fact. One theory in Philosophy is determinism: the idea that the future is entirely decided by the past plus the laws of nature. That is, if you could rewind time and play it back a hundred times, leaving the laws of nature the same, everything would play out the exact same way. Some philosophers argue that determinism is incompatible with free will; others, that our actions can be fully determined, but our choices in making them still free. That’s often the argument made by religious believers: that God knows each of our actions before we make them, but that doesn’t invalidate our choice in making them.
Others still hold that determinism is wrong because it neglects the role of chance, but that even with chance, we still lack free will. Imagine that you’re driving somewhere. If a particular traffic light is green, you’ll take one route, but if it’s red, you’ll go a different way, because it’ll be quicker. The colour of the traffic light is down to chance, but your choice is still not made freely. And there are countless further perspectives on the question beyond this, including drawing distinctions between choosing freely and acting freely, between our first-order desires (what we want, e.g. to fall asleep in a boring lecture) and our second-order desires (what we want to want, e.g. to want the lecture to go on for another two hours because we’re such good students). Informed by scientific progress, these debates in Philosophy continue to evolve.

Image credits: statue, virtual reality, neuron, justice, wilderness.