Critical thinking everywhere
So we’ve said critical thinking works in science through a number of channels - the most obvious of which is the experiment. If something disagrees with experiment then typically (but not always mind you) it means the idea being tested is false (but we can never rule out the fact there are rare cases where it can also mean there is a flaw with the experiment, as said earlier). But this split in frequency - more often a theory is wrong when the experimental results disagree with it than that the experimental results are wrong in some way and the theory is right can tell you nothing whatever about which situation you are in when you encounter this problem. Anyways, as we said experiments are not the whole story. We must ask: what is the accompanying explanation? If there is none - we have explanationless science. In other words we have the facade of science - the thin veneer - an imposter - the shape of science only. Science is ultimately about explanations of the physical world. Not experiments. Both are necessary however.
What about in mathematics? Well there experiments are (typically) not needed (although there are exceptions to this-the so-called 4 colour theorem in mathematics which says that you only need 4 colours on a map to colour it so that no two adjacent regions have the same colour - which is kind of a surprising result if you’ve never thought about it before. Anyways - in a sense - this did require an experiment of a kind - it was proved using a computer to check possibilities in abstract space that were just too numerous for a human to do). Whatever the case, in mathematics we less often speak of experiments as we do of proofs which then serve as refutations or criticisms. A proof of a theorem is a criticism of its negation. Or in mathematics we might perform on a completely abstract equality of some kind a substitution where the result disagrees with the prediction of the theorem (a special case of a reductio-ad-absurdum).
Or if we know some known result holds (like say Pythagoras’ theorem) and we actually substitute in numbers and the equality does not hold, we know there’s an error. Identifying an error is a criticism. And that allows progress too. Identifying and correcting errors in this way. If we have a general case we know is our best explanation (like Pythagoras) and a purported special case fails we have a problem. Maybe we’ve disproved Pythagoras’ theorem? More likely we have made an error in our substitution and subsequent calculations or both.
Basically criticism in mathematics amounts to computations (i.e: workings/calculations) that show some theorem - some guess - is wrong.
I say that again: it is about showing something is wrong.
This is the role of criticism. I feel I must labour the point. Criticism is about showing that, and how, something is wrong. And the criticism itself is accompanied by some explanation as well - a reason WHY some thing is wrong.
In history - it works much as in science - a new idea about the past is put forth. We criticise it (which amounts to something like evaluating it against other known sources, other kinds of evidence - we are comparing our theories of the evidence to our knew theory of what might have happened in the past). It is a clash, as in science, between theories: evidence and new explanation.
In music: that a combination of sounds is less pleasing than another is a criticism. The waste paper basket of the composer is filled with criticisms - which may indeed be inexplicit - but they are real. But how to come up with good criticisms? Here we find a crossover - and it is no accident. We are humans - not machines. We think. We do not simply follow an automatic algorithm like a computer. How to come up with good criticisms?
We must create them.
So criticism is a creative act. Creativity is needed. And in some sense this then means that the “critical thinking” vs “creative thinking” distinction is, in a sense, false. There is no dichotomy here - it’s all creativity of a kind. Now while that is true, distinctions are useful. There is a species of creative thought that we designate as being “criticism”. As I have alluded to: this critical thinking part is the stuff we have a lot of knowledge about. As such there are useful heuristics - rules - about how to go about methodically in order to check your guesses, to identify errors (and possibly correct them) to find the problems. And the thing about criticisms is we can always invent new ways of criticising. But there is a useful distinction here between creativity that is pure imagination and criticism. And when those two work together to create something new we have innovation.
But aside from what we have said so far about kinds of criticism: those being experiment, the presence or lack of good explanations, the possibility of a proof or disproof - what else do we have? We may just have so-called “rules of thumb”: things that seem to work - rules that generally are applied in some subject area or other in order to check if your new creation conforms to the standards expected in that area (here I’m thinking artistic or engineering endeavours). But of course sometimes new kinds criticisms are needed (a new way of performing experiments, say - or the invention of new equipment and so forth). Criticism - showing how something is wrong can take quite the act of creativity.
But let us just keep in view, for the moment, that critical thinking is at heart about showing how something is wrong. To what end? To improve things! It could be to improve ourselves - quite literally - improve our own thinking. To get something right that was wrong. To create a better product - whatever that might be. This is the purpose - and so, what a wonderful purpose criticism serves - improvement and progress. Why it has such a bad name, I am not entirely sure.
But I guess it has something to do with two mistakes: one the distinction make between "constructive and destructive" criticism. All criticism aims at destruction for the purpose of construction. It aims to destroy a less good idea to replace it with a newly constructed better, truer idea.
So that distinction is, I think, confused in the minds of people. But there is also the concern that criticisms might be applied to people. And here I do understand the concern. One should always be careful to focus on the ideas, not the person. We are criticising ideas. Not people. People have ideas. But they are not identical to ideas. This is important. Of course some people are emotionally wedded, and deeply, to some ideas. If we value those people-their feelings-then yes. We must ask them if they care for us to continue to criticise their own ideas if such criticism is painful to them. But these issues are, in the broader scheme, details and not walls before us. When discussing progress in science, or mathematics or philosophy or whatever else is of academic value to us in the creation of knowledge we must as far as we possibly can, keep emotions in check. And not let ourselves be hurt when critical thinking is applied to our own ideas. Those who do not wish to participate in this growth of knowledge should never be forced. We need not include them in this. The ethics of critical thinking is thus, reasonably straight forward. It is about applying the method to ideas. Not to people. And that method: attempting to show the ideas as wrong for the purpose of making improvements is not well known. If I can offer some practical advice here, in discussions (in person, using the spoken word, people tend to do this as a matter of course in the English speaking world - it is more natural) - but not in the written or online world. The error is this: the use of the 2nd person. Namely the word “you” or any synonym. As soon as a sentence contains the word “you” - Y-O-U you - things have become personalised and if it’s a criticism - accusatory. It’s an easy shift to make. Instead focus on the ideas. My own tactic is to either drop the word altogether or use the word “one” O-N-E wherever I might otherwise use Y-O-U.
Whatever the case, personalising a discussion - especially about abstract academic topics, is a criticism. So saying “You are personalising things by talking about yourself or myself” doesn’t work as well as, simply ignoring whatever the claim about yourself or myself was…and proceeding by focussing on the content. But this topic of how to have discussions is itself a whole other subject and I’ve rarely found people are much interested in having it. One reason is, almost everything thinks they are very good at discussion - of course they are -they’ve been talking since they were toddlers - why wouldn’t they be expert at it by now? Well one reason is that we are, all of us, inheritors of a particular culture. And some cultures more than others can have an accusatory way of speaking which almost immediately degenerates into talking about people rather than ideas. It’s very hard to bring such discussions back on the rails once they are off the rails. The criticisms have become focussed on people’s personalities or tone or any of a number of personal attributes and completely away from the idea under discussion.
Critical thinking is about criticising ideas. Not people. It can criticise the ideas people have - but that should not hurt people. There are exceptions of course: some people are religiously wedded to some ideas. To even suggest that the spaghetti monster might not be an actual living being could be cause hurt to some people. But the reasons for that feeling of hurt can themselves be criticised without criticising the person or the imaginary god. It’s a deep area. And this is merely a sketch of critical thinking.
The substance of all of this is, of course not an idea that originated with me - or entirely with any one person. And yet we can name one person above all others who really defined the field: Karl Popper.
Perhaps more than any other person this philosopher set out the scheme over a number of years in a variety of books on the topic. His books were never called “Critical Thinking” and perhaps that is why they are not as well known in educational circles as they should be. His books were titled “The Logic of Scientific Discovery” and “Conjectures and Refutations” and “Objective Knowledge” and he has come to be known as a philosopher of science and politics - and certainly his contributions in those areas were as fundamentally groundbreaking and objectively progressive as Einstein’s were in physics, or Mozart's were in music. But for education - he explained how knowledge is created - that is - how learning can take place. And importantly for my purposes here: what the critical method actually is. His philosophy has come to be known as critical rationalism. And that is the philosophy of critical thinking.
It is astonishing that Popper’s critical rationalism does not inform how cultures, communities, families, parents and dare we say schools and universities help to improve learning. Children are natural learners. They go out into the world and without hangups and fears guess and check. They experiment. The only reason they slow down is because they learn ideas from authorities about what to be fearful of, what is the wrong thing to do and why to be scared and who should be listened to and therefore why some things should not be tried out and tested. Over years and then decades the ballast of bad anti-rational anti-critical ideas are learned and then frame what a person can think about.
So some kind of explicit critical thinking can help to undo at least some of this. Popper got there. Popper identified how knowledge is created and therefore how learning must operate. But it is in an ideal sense. It is in the sense of: if you do not have what are called “hang ups” - things you do not like thinking about or doing. These are caused by what David Deutsch terms anti-rational memes - ideas that hold themselves immune from criticism. Identifying and correcting those - well that is very hard and we would need yet another podcast all about that. As new as critical rationalism is on the scene (so new it barely even gets any mention in any form ever in the formal educational institutions despite being the theory of learning) the concept of anti-rational memes is newer still.
But let’s stick to the basics for the moment - how can we teach people who want to know about this critical thinking stuff more of it? Especially young people?
Well, firstly, - don’t. Don’t teach them as in do not force instruction on them unless they ask. That’s part of the anti-critical problem. A person needs to have a problem in the first place. Someone has to ask first. And when they ask about something then the conversation can begin about how we can come to know that thing or anything else. And what I am about to say comes with an important caveat I will return to at the end. There is no formula to being a good critical thinker. There is no fixed set of rules or even as I will say heuristics. There are some useful hints. But learning these by rote would be anti-critical. Any university can provide you with a list of critical thinking techniques. I think they’re mostly largely misguided (and I will come back to that later) - but what I want to do here is concentrate on criticism. What are the modes of criticism that can be employed to actually help someone be a critical thinker rather than just “achieve better marks” or fulfil the requirements of some task undertaken at school or university.
Depending on the level someone is at - let’s consider a teenager - I find two principles useful in guiding the capacity to think critically about any topic. Whether it is something in the media or something in a book or something you are trying to learn:
1. Assume what you are presented with is false.
2. Now find out why.
This is not to say you will find out why it’s false. That’s just an assumption after all. In reality many times what you are learning is the best present understanding of a thing. But the very act of trying to uncover what is false about an idea reveals what is true about an idea - or nearer to true about an idea. If some claim fails to be refuted by your attempts to find out why it’s false - in other words if an idea survives your criticisms: you’ve learned a lot.
Now trying to find out why some idea is - possibly - false entails quite a vast amount of creativity. It requires one to create criticisms. You have to create them in your own mind but - happily there are well trodden paths worn by great thinkers who have gone before. Philosophy - the best sort - is a tool box of criticisms. So is your own background knowledge and of course so is the corpus of knowledge out there. You can check any claim against what else is known and all of it in light of the deepest principles we have - things that I have mentioned before like whether there is a good explanation lurking behind it all. But if I were helping someone improve that general skill or set of heuristics we call critical thinking I would ask them to begin by considering if the idea under review meshes well with all other important ideas. Is it strictly contradicted by anything you know? If we cannot think of something (for example if a news story says that video has emerged from the forests of Canada purporting to show a non-human ape loose on a continent without apes - is the explanation that it is actually an ape or that an error has been made? Are we contradicting what we know about “apes loose in Canadian forests?”
But if we cannot find such a contradiction or obvious contradiction, consider: Does a law of epistemology contradict it? (So - if it is a scientific claim - is it testable?). Now let’s consider: does a known law of science contradict it? (Does it demand an infinite supply of instant energy? Does it assume the laws of thermodynamics are false?).
For some other claims especially in the political or economic realm we can ask of it: Is it immoral? (On balance, would it force free and peaceful people to do other than what they want to? Would it, on average, lower the well being of all conscious creatures? Does it entail theft?).
Here are some more useful guides to being a good critical thinker in the critical rationalist tradition.
Does the idea rely solely upon an appeal to authority? Are we asked to believe it because some politician, priest, scientist, book or doctor just says it is true? Do you understand the idea? That itself is a criticism. This does not mean it is false, necessarily - but if you do not understand it - and you have tried hard - this is a criticism of the idea in terms of its expression: it has not been properly explained to you. It is not sufficiently clear - to you.
So: Is the idea being expressed in simple language?
This is related to an even deeper criticism, perhaps the deepest of all, Deutsch’s anti-rational principle we might call it. The question here is:
Does this idea hold itself immune from criticism in any way?
That is fundamental. That entails almost everything else once we have exhausted everything else we have thought of. It entails: is it clearly expressed? Does it “stick its neck out” in its predictions about the physical world? Does it claim to know things that cannot possibly be known? (like the state of the planet Earth next year. Or 100 years.) Is it a claim so general as to be vacuous and thus hold itself immune from criticism. For example: “There should be no pollution”. Or “The children are our future” or “Do what is right”.
So these are some of the way criticism works. There are many many more. One could consider the long and interesting list of so-called “logical fallacies" that can be found in many places on the internet. Just consider as many ways as possible that the idea is lacking or false. If it survives all your attempts to criticise it - then it just might contain something worth knowing. It could still be false, of course. We expect even our most cherished explanations to turn out false in the final analysis. Things can always unexpectedly turn out false. You just might not be imaginative (that is creative) enough to find out what its flaw is - but you have actually used a critical method to try to knock it down. You have thought critically.
Your failure to find a flaw could simply be a failure of imagination. Some famous philosophers like to use a phrase similar to “We cannot imagine how it could be otherwise” - like “We cannot imagine any other basis for morality than conscious creatures” or “We cannot imagine any way in which the speed of light could be exceeded” or pick your most cherished so-called “self evident truth”.
One's very human and subjective failure of imagination is neither an objective proof or disproof.
This is what proper philosophers do as their business. Or what they should do. What many - ok, ok some - have done in the past. Philosophy as I have said many times and as is echoed in the work of David Deutsch - indeed has a deservedly bad reputation. Much of what marches under the banner of “philosophy” is not really anything of the sort. Philosophy as a subject ranges from the focused study of all that is rational in the most careful and deliberate way, through to more esoteric matters - through to, yes, utter nonsense. Philosophy, most broadly considered, is a mess. In this subject it is as if we were to call astrology, creationism and ghost hunting science along with biology and physics. As if we were to call the sound of a riot in the streets "music".
Such redefinitions would be a serious problem for the term "music" or indeed “science” but it would do nothing whatsoever to actually bear upon the question of what is true, or not in (say) physics. That would still be adjudicated by the critical methods of experiment and theory I have already outlined.
So - although you may hear that Karl Popper was a philosopher and that epistemology and critical rationalism are types of philosophy - this does not mean they are mere opinions. They are rigorous formulations and sets of intertwined ideas, themselves criticised and refined over many years and which explain, above all else, how knowledge grows and what techniques work best in sifting good ideas from bad. That is the topic of critical thinking. Critical thinking is about showing what is wrong with ideas so that better ones can be produced and we can get ever closer to the truth by discovering more of it. We understand much about this critical process. About critical thinking. That so many people who use the term “critical thinking” appear never to have even heard of Karl Popper let alone “critical rationalism” as a world view has absolutely zero bearing on what critical thinking truly is. It is what it is. As physics is what it is, even if some people who know next to nothing about it claim to. But we have so far concentrated on half the story. What about creativity? How does that work?
So we’ve said critical thinking works in science through a number of channels - the most obvious of which is the experiment. If something disagrees with experiment then typically (but not always mind you) it means the idea being tested is false (but we can never rule out the fact there are rare cases where it can also mean there is a flaw with the experiment, as said earlier). But this split in frequency - more often a theory is wrong when the experimental results disagree with it than that the experimental results are wrong in some way and the theory is right can tell you nothing whatever about which situation you are in when you encounter this problem. Anyways, as we said experiments are not the whole story. We must ask: what is the accompanying explanation? If there is none - we have explanationless science. In other words we have the facade of science - the thin veneer - an imposter - the shape of science only. Science is ultimately about explanations of the physical world. Not experiments. Both are necessary however.
What about in mathematics? Well there experiments are (typically) not needed (although there are exceptions to this-the so-called 4 colour theorem in mathematics which says that you only need 4 colours on a map to colour it so that no two adjacent regions have the same colour - which is kind of a surprising result if you’ve never thought about it before. Anyways - in a sense - this did require an experiment of a kind - it was proved using a computer to check possibilities in abstract space that were just too numerous for a human to do). Whatever the case, in mathematics we less often speak of experiments as we do of proofs which then serve as refutations or criticisms. A proof of a theorem is a criticism of its negation. Or in mathematics we might perform on a completely abstract equality of some kind a substitution where the result disagrees with the prediction of the theorem (a special case of a reductio-ad-absurdum).
Or if we know some known result holds (like say Pythagoras’ theorem) and we actually substitute in numbers and the equality does not hold, we know there’s an error. Identifying an error is a criticism. And that allows progress too. Identifying and correcting errors in this way. If we have a general case we know is our best explanation (like Pythagoras) and a purported special case fails we have a problem. Maybe we’ve disproved Pythagoras’ theorem? More likely we have made an error in our substitution and subsequent calculations or both.
Basically criticism in mathematics amounts to computations (i.e: workings/calculations) that show some theorem - some guess - is wrong.
I say that again: it is about showing something is wrong.
This is the role of criticism. I feel I must labour the point. Criticism is about showing that, and how, something is wrong. And the criticism itself is accompanied by some explanation as well - a reason WHY some thing is wrong.
In history - it works much as in science - a new idea about the past is put forth. We criticise it (which amounts to something like evaluating it against other known sources, other kinds of evidence - we are comparing our theories of the evidence to our knew theory of what might have happened in the past). It is a clash, as in science, between theories: evidence and new explanation.
In music: that a combination of sounds is less pleasing than another is a criticism. The waste paper basket of the composer is filled with criticisms - which may indeed be inexplicit - but they are real. But how to come up with good criticisms? Here we find a crossover - and it is no accident. We are humans - not machines. We think. We do not simply follow an automatic algorithm like a computer. How to come up with good criticisms?
We must create them.
So criticism is a creative act. Creativity is needed. And in some sense this then means that the “critical thinking” vs “creative thinking” distinction is, in a sense, false. There is no dichotomy here - it’s all creativity of a kind. Now while that is true, distinctions are useful. There is a species of creative thought that we designate as being “criticism”. As I have alluded to: this critical thinking part is the stuff we have a lot of knowledge about. As such there are useful heuristics - rules - about how to go about methodically in order to check your guesses, to identify errors (and possibly correct them) to find the problems. And the thing about criticisms is we can always invent new ways of criticising. But there is a useful distinction here between creativity that is pure imagination and criticism. And when those two work together to create something new we have innovation.
But aside from what we have said so far about kinds of criticism: those being experiment, the presence or lack of good explanations, the possibility of a proof or disproof - what else do we have? We may just have so-called “rules of thumb”: things that seem to work - rules that generally are applied in some subject area or other in order to check if your new creation conforms to the standards expected in that area (here I’m thinking artistic or engineering endeavours). But of course sometimes new kinds criticisms are needed (a new way of performing experiments, say - or the invention of new equipment and so forth). Criticism - showing how something is wrong can take quite the act of creativity.
But let us just keep in view, for the moment, that critical thinking is at heart about showing how something is wrong. To what end? To improve things! It could be to improve ourselves - quite literally - improve our own thinking. To get something right that was wrong. To create a better product - whatever that might be. This is the purpose - and so, what a wonderful purpose criticism serves - improvement and progress. Why it has such a bad name, I am not entirely sure.
But I guess it has something to do with two mistakes: one the distinction make between "constructive and destructive" criticism. All criticism aims at destruction for the purpose of construction. It aims to destroy a less good idea to replace it with a newly constructed better, truer idea.
So that distinction is, I think, confused in the minds of people. But there is also the concern that criticisms might be applied to people. And here I do understand the concern. One should always be careful to focus on the ideas, not the person. We are criticising ideas. Not people. People have ideas. But they are not identical to ideas. This is important. Of course some people are emotionally wedded, and deeply, to some ideas. If we value those people-their feelings-then yes. We must ask them if they care for us to continue to criticise their own ideas if such criticism is painful to them. But these issues are, in the broader scheme, details and not walls before us. When discussing progress in science, or mathematics or philosophy or whatever else is of academic value to us in the creation of knowledge we must as far as we possibly can, keep emotions in check. And not let ourselves be hurt when critical thinking is applied to our own ideas. Those who do not wish to participate in this growth of knowledge should never be forced. We need not include them in this. The ethics of critical thinking is thus, reasonably straight forward. It is about applying the method to ideas. Not to people. And that method: attempting to show the ideas as wrong for the purpose of making improvements is not well known. If I can offer some practical advice here, in discussions (in person, using the spoken word, people tend to do this as a matter of course in the English speaking world - it is more natural) - but not in the written or online world. The error is this: the use of the 2nd person. Namely the word “you” or any synonym. As soon as a sentence contains the word “you” - Y-O-U you - things have become personalised and if it’s a criticism - accusatory. It’s an easy shift to make. Instead focus on the ideas. My own tactic is to either drop the word altogether or use the word “one” O-N-E wherever I might otherwise use Y-O-U.
Whatever the case, personalising a discussion - especially about abstract academic topics, is a criticism. So saying “You are personalising things by talking about yourself or myself” doesn’t work as well as, simply ignoring whatever the claim about yourself or myself was…and proceeding by focussing on the content. But this topic of how to have discussions is itself a whole other subject and I’ve rarely found people are much interested in having it. One reason is, almost everything thinks they are very good at discussion - of course they are -they’ve been talking since they were toddlers - why wouldn’t they be expert at it by now? Well one reason is that we are, all of us, inheritors of a particular culture. And some cultures more than others can have an accusatory way of speaking which almost immediately degenerates into talking about people rather than ideas. It’s very hard to bring such discussions back on the rails once they are off the rails. The criticisms have become focussed on people’s personalities or tone or any of a number of personal attributes and completely away from the idea under discussion.
Critical thinking is about criticising ideas. Not people. It can criticise the ideas people have - but that should not hurt people. There are exceptions of course: some people are religiously wedded to some ideas. To even suggest that the spaghetti monster might not be an actual living being could be cause hurt to some people. But the reasons for that feeling of hurt can themselves be criticised without criticising the person or the imaginary god. It’s a deep area. And this is merely a sketch of critical thinking.
The substance of all of this is, of course not an idea that originated with me - or entirely with any one person. And yet we can name one person above all others who really defined the field: Karl Popper.
Perhaps more than any other person this philosopher set out the scheme over a number of years in a variety of books on the topic. His books were never called “Critical Thinking” and perhaps that is why they are not as well known in educational circles as they should be. His books were titled “The Logic of Scientific Discovery” and “Conjectures and Refutations” and “Objective Knowledge” and he has come to be known as a philosopher of science and politics - and certainly his contributions in those areas were as fundamentally groundbreaking and objectively progressive as Einstein’s were in physics, or Mozart's were in music. But for education - he explained how knowledge is created - that is - how learning can take place. And importantly for my purposes here: what the critical method actually is. His philosophy has come to be known as critical rationalism. And that is the philosophy of critical thinking.
It is astonishing that Popper’s critical rationalism does not inform how cultures, communities, families, parents and dare we say schools and universities help to improve learning. Children are natural learners. They go out into the world and without hangups and fears guess and check. They experiment. The only reason they slow down is because they learn ideas from authorities about what to be fearful of, what is the wrong thing to do and why to be scared and who should be listened to and therefore why some things should not be tried out and tested. Over years and then decades the ballast of bad anti-rational anti-critical ideas are learned and then frame what a person can think about.
So some kind of explicit critical thinking can help to undo at least some of this. Popper got there. Popper identified how knowledge is created and therefore how learning must operate. But it is in an ideal sense. It is in the sense of: if you do not have what are called “hang ups” - things you do not like thinking about or doing. These are caused by what David Deutsch terms anti-rational memes - ideas that hold themselves immune from criticism. Identifying and correcting those - well that is very hard and we would need yet another podcast all about that. As new as critical rationalism is on the scene (so new it barely even gets any mention in any form ever in the formal educational institutions despite being the theory of learning) the concept of anti-rational memes is newer still.
But let’s stick to the basics for the moment - how can we teach people who want to know about this critical thinking stuff more of it? Especially young people?
Well, firstly, - don’t. Don’t teach them as in do not force instruction on them unless they ask. That’s part of the anti-critical problem. A person needs to have a problem in the first place. Someone has to ask first. And when they ask about something then the conversation can begin about how we can come to know that thing or anything else. And what I am about to say comes with an important caveat I will return to at the end. There is no formula to being a good critical thinker. There is no fixed set of rules or even as I will say heuristics. There are some useful hints. But learning these by rote would be anti-critical. Any university can provide you with a list of critical thinking techniques. I think they’re mostly largely misguided (and I will come back to that later) - but what I want to do here is concentrate on criticism. What are the modes of criticism that can be employed to actually help someone be a critical thinker rather than just “achieve better marks” or fulfil the requirements of some task undertaken at school or university.
Depending on the level someone is at - let’s consider a teenager - I find two principles useful in guiding the capacity to think critically about any topic. Whether it is something in the media or something in a book or something you are trying to learn:
1. Assume what you are presented with is false.
2. Now find out why.
This is not to say you will find out why it’s false. That’s just an assumption after all. In reality many times what you are learning is the best present understanding of a thing. But the very act of trying to uncover what is false about an idea reveals what is true about an idea - or nearer to true about an idea. If some claim fails to be refuted by your attempts to find out why it’s false - in other words if an idea survives your criticisms: you’ve learned a lot.
Now trying to find out why some idea is - possibly - false entails quite a vast amount of creativity. It requires one to create criticisms. You have to create them in your own mind but - happily there are well trodden paths worn by great thinkers who have gone before. Philosophy - the best sort - is a tool box of criticisms. So is your own background knowledge and of course so is the corpus of knowledge out there. You can check any claim against what else is known and all of it in light of the deepest principles we have - things that I have mentioned before like whether there is a good explanation lurking behind it all. But if I were helping someone improve that general skill or set of heuristics we call critical thinking I would ask them to begin by considering if the idea under review meshes well with all other important ideas. Is it strictly contradicted by anything you know? If we cannot think of something (for example if a news story says that video has emerged from the forests of Canada purporting to show a non-human ape loose on a continent without apes - is the explanation that it is actually an ape or that an error has been made? Are we contradicting what we know about “apes loose in Canadian forests?”
But if we cannot find such a contradiction or obvious contradiction, consider: Does a law of epistemology contradict it? (So - if it is a scientific claim - is it testable?). Now let’s consider: does a known law of science contradict it? (Does it demand an infinite supply of instant energy? Does it assume the laws of thermodynamics are false?).
For some other claims especially in the political or economic realm we can ask of it: Is it immoral? (On balance, would it force free and peaceful people to do other than what they want to? Would it, on average, lower the well being of all conscious creatures? Does it entail theft?).
Here are some more useful guides to being a good critical thinker in the critical rationalist tradition.
Does the idea rely solely upon an appeal to authority? Are we asked to believe it because some politician, priest, scientist, book or doctor just says it is true? Do you understand the idea? That itself is a criticism. This does not mean it is false, necessarily - but if you do not understand it - and you have tried hard - this is a criticism of the idea in terms of its expression: it has not been properly explained to you. It is not sufficiently clear - to you.
So: Is the idea being expressed in simple language?
This is related to an even deeper criticism, perhaps the deepest of all, Deutsch’s anti-rational principle we might call it. The question here is:
Does this idea hold itself immune from criticism in any way?
That is fundamental. That entails almost everything else once we have exhausted everything else we have thought of. It entails: is it clearly expressed? Does it “stick its neck out” in its predictions about the physical world? Does it claim to know things that cannot possibly be known? (like the state of the planet Earth next year. Or 100 years.) Is it a claim so general as to be vacuous and thus hold itself immune from criticism. For example: “There should be no pollution”. Or “The children are our future” or “Do what is right”.
So these are some of the way criticism works. There are many many more. One could consider the long and interesting list of so-called “logical fallacies" that can be found in many places on the internet. Just consider as many ways as possible that the idea is lacking or false. If it survives all your attempts to criticise it - then it just might contain something worth knowing. It could still be false, of course. We expect even our most cherished explanations to turn out false in the final analysis. Things can always unexpectedly turn out false. You just might not be imaginative (that is creative) enough to find out what its flaw is - but you have actually used a critical method to try to knock it down. You have thought critically.
Your failure to find a flaw could simply be a failure of imagination. Some famous philosophers like to use a phrase similar to “We cannot imagine how it could be otherwise” - like “We cannot imagine any other basis for morality than conscious creatures” or “We cannot imagine any way in which the speed of light could be exceeded” or pick your most cherished so-called “self evident truth”.
One's very human and subjective failure of imagination is neither an objective proof or disproof.
This is what proper philosophers do as their business. Or what they should do. What many - ok, ok some - have done in the past. Philosophy as I have said many times and as is echoed in the work of David Deutsch - indeed has a deservedly bad reputation. Much of what marches under the banner of “philosophy” is not really anything of the sort. Philosophy as a subject ranges from the focused study of all that is rational in the most careful and deliberate way, through to more esoteric matters - through to, yes, utter nonsense. Philosophy, most broadly considered, is a mess. In this subject it is as if we were to call astrology, creationism and ghost hunting science along with biology and physics. As if we were to call the sound of a riot in the streets "music".
Such redefinitions would be a serious problem for the term "music" or indeed “science” but it would do nothing whatsoever to actually bear upon the question of what is true, or not in (say) physics. That would still be adjudicated by the critical methods of experiment and theory I have already outlined.
So - although you may hear that Karl Popper was a philosopher and that epistemology and critical rationalism are types of philosophy - this does not mean they are mere opinions. They are rigorous formulations and sets of intertwined ideas, themselves criticised and refined over many years and which explain, above all else, how knowledge grows and what techniques work best in sifting good ideas from bad. That is the topic of critical thinking. Critical thinking is about showing what is wrong with ideas so that better ones can be produced and we can get ever closer to the truth by discovering more of it. We understand much about this critical process. About critical thinking. That so many people who use the term “critical thinking” appear never to have even heard of Karl Popper let alone “critical rationalism” as a world view has absolutely zero bearing on what critical thinking truly is. It is what it is. As physics is what it is, even if some people who know next to nothing about it claim to. But we have so far concentrated on half the story. What about creativity? How does that work?