These are the common strands that run through our thought processes when we think we perceive "opposites".
Opposites as Assumptions - We state that one thing is the opposite of another because it makes it easy to think about and makes it easy to classify things.
Opposites as Traditions - Lots of assumptions have become traditional parts of culture, so that questioning their truth is seen as ridiculous.
Rhetorical Opposites - Many opposites are only English turns of phrase that have no logic behind them, but yet the ideas still occasionally inform our concepts of what is true and correct. Such careless talk is suited to poetry and light-hearted communication but should be guarded against in any serious attempt to understand reality.
Anthropocentric Opposites are scales based around Human experience. We create arbitrary opposites and scientifically meaningless scales. They serve well for social communication and quick discussion but are ultimately relativistic, subjective, misleading and false.
Numerical Scale Errors - When a scale has no upper value, or no lower value, it is impossible for logical opposites to exist. On the scale from "zero" to an undefined upper value, it is impossible to say what the opposite of "10" units or "4000" units is. Because there is no central pole, opposites become meaningless. Any scale that has no logical end is devoid of opposites. Likewise, any scale that has no logical center cannot have real opposites.
Absolutism - The failure to realize that most opposites are relational is an error of absolutism. In a poor community the richest and poorest might consider themselves opposites, but compared to the wealth of a rich American, both would be considered poor. If we accept that most opposites are not absolute, but relative to a particular context, we admit that those opposites are rhetorical and subjective, not philosophically or scientifically meaningful.
It is hard to get a grip on the idea that opposites are illusory without delving into examples. So what follows are many commonly stated opposites plus descriptions of the underlying realities that falsify the idea of them as opposites.
“Magnitude, n. Size. Magnitude being purely relative, nothing is large and nothing is small. If everything in the universe were increased in bulk one thousand diameters nothing would be any larger than it was before, but if one thing remained unchanged all the others would be larger than they had been.”
A limited scale starts at its lower value and moves past its centre to its upper value. So, the opposite of the upper value is the lowest value. We like to place most of our experience of things on scales. So, we would place "bliss" on one end of a scale and "nihilism" on the other and call them opposites. Less extreme opposites on the same scale would include "happiness" and "sadness". In the middle of such scales is a neutral value that has no opposite, "neither happy or sad". In nearly all scales, the "center" is arbitrary, defined by us Humans for no real reason other than that it makes it easy for us to communicate.
This is best demonstrated by looking at real examples of proposed opposites. The first one (Rich and Poor) should highlight the fact that items on linear scales have no real opposites:
There are two reason why "rich and poor" are not opposites. Firstly: what is the opposite of lots of money? Is it no money? The opposite of a rich person could indeed be a person so poor that they have nothing. So, a rich man of £1 000 000 is the opposite of the man with £0. What is the opposite of a man with £1 000 000 debt (£-1 000 000)? This man is also the opposite of the man with £1 000 000 pounds. What about a man with £2 000 000 pounds? His opposites must be men with both £0 and -£2 000 000. A value cannot have two opposites as it leads to contradiction and ambiguity. What is the opposite of a person with £0? We can see there is no opposite. Is it a person with £1 000, £10 000 or £100 000 pounds? There is no logical reason to conclude that someone who is the opposite of our £0 person has any particular amount of money. It is logical nonsense to say that "rich" and "poor" have opposites.
Secondly, it only serves as a rhetorical statement about relative wealth. Who is "rich" in one country can easily be considered poor in another, and who is poor in one community can be considered rich by others. There is no objective criteria. "Rich" and "poor" aren't opposites but merely comparisons.
We say "hot" and "cold" are opposites. But this is arbitrary and sheds no useful light on the universe. They're not opposites, just comparisons. This is for three reasons:
Compare two actual temperatures like boiling-hot (100°C) and freezing-cold (0°C): are they opposites? If they are opposites, then, 200°C (very hot!) is not the opposite of 0°C, because we've just defined the opposite of 0°C as 100°. And, why is -100 °C not the opposite of 100 °C? The concept of opposite temperatures is flawed and whenever we try to find out what the opposite it, we hit contradictions.
Secondly, both 0 degrees and 100 degrees are freezing cold relative to the temperature of other parts of the universe, and both are likewise best considered very hot compared to the endless coldness of space which extends well into minus-hundreds-of-degrees-celsius. This makes "hot" and "cold" comparisons, not opposites.
Thirdly, if you measure temperature in degrees Kelvin it highlights the fact that the numbers are arbitrary. Why would anyone say that 373°K is the opposite of 273°K? They're random numbers. They happen to be the freezing-point and boiling-point of water in Kelvins. But they're not opposites in any physical sense, just values based on the properties of H2O. With no upper limit to temperature and no central axis on the scale, temperatures do not have opposites, even though it suits us in common language to talk as if they do, because it makes speech simpler.
“By convention sweet, by convention bitter, by convention hot, by convention cold, by convention colour: but in reality atoms and void.”
Black and white are "colours". Colours are specific wavelengths of light on the Electromagnetic Spectrum. Outside of "Red" there is "Infrared", outside of Violet there is "Ultraviolet", and outside of this scale is an almost infinite spectrum of frequencies. All that defines the "colour" is an arbitrary human appreciation that differs from one person to another.
Everyone is capable of seeing different spreads of colours; just like one person can hear a different height of pitch to another person, one person is more sensitive to reds or blues than another. All colours differ from person to person.
"White" as a colour is a mix of multiple frequencies of light. "Black" as a colour is the lack of these frequencies. But in all "black" there are many frequencies we can't see. We could be looking at an intense source of radiation and call it "black" merely because we can't see its output. There could be a source of light that contains millions of frequencies across the spectrum, but this would be a completely different "white" to a source of light that was emitting only visible light. There is no single logical "white" light. Likewise there is no single "black". A black location could merely lack visible light or it could be too dim to make out (for many people, but not all), or it could lack all radiation and be completely black.
So you could have a black object that is radiating brilliantly at many frequencies, and a black that is radiating at none. They are "opposites" in one sense. But in the sense of visible light, they both look black. What we call "black" and "white" and how we define them as opposites are Human-only homocentric definitions; in terms of physical reality our "opposites" are logical nonsense, arbitrary and made-up to suit us, and not descriptions of reality. 'Black' and 'White' are only called opposites because it suits our speech but as such considering them 'opposites' is delusional and misleading unless you really do understand the nature of light and our eyes!
"Every action has an equal and opposite reaction" is a physical law that means for every force, the vector sum of opposite forces causes overall neutralization. This is required for the conservation of energy. But what is a "force" and what is an "opposite" force?
All forces have properties of physical location, direction, strength and direction in time. What we call "opposite" forces are merely forces with many properties that are equal and only one or two that are opposite. Note that the strength of a force is measured in Newtons (N). So, if a force is exerting itself Northwards at 20N, the opposite force is one that contains many similar properties: Its effective vectoral position in space is the same as the other force, its sum strength is also the same, and its medium is the same. Its direction is opposite, but only across one axis. What we call an "opposite" only has one opposite property, all the rest are the same. Clearly what we mean by "opposite" in science is very much not a completely logical opposite, but a useful phrase to mean that one property, when added to its antagonist, equals zero. The overall vector force of any interaction is zero, but we call it an "opposite" despite being unable, logically, to state which property is the opposite without knowing the assumptions of the speaker.
For example if we have an electron moving "Northwards" with energy of 0.2MeV, what is an "opposite" to it? Just referencing an "opposite" to it does not suffice without assumptions or context because there is no true "opposite" to an object or force. We could say an opposite is a positron, the same speed, direction, etc, but with a positive charge. When they touch, they annihilate. Or, we could say its opposite is an electron that is physically "opposite" our electron in a room. Or maybe it is traveling in the opposite direction on a particular axis. Without an underlying assumption about reality, our "opposite" electron doesn't exist and is not a precise object. The thinking process around naming something an "opposite" relies on assumption and context, because there are no true 'opposites' to particles or forces.
When certain particles collide, they annihilate each other. Both particles are destroyed, and a variety of photons (pure energy) and different particles emerge from the fray. Supercolliders are heady scientific devices to smash particles together at high power in order to study the resultant particles. As electrons and positrons annihilate each other when they meet, are they opposites? I think not: they only sound like opposites in simplified rhetorical arguments. Three strong arguments refute the idea that electrons have an opposite:
Firstly, both electrons and their 'opposite' are leptons (along with neutrinos), with a certain spin, charge, direction, energy, speed and negligible mass. It doesn't make sense to say that an "electron" is the opposite of a "negatron" rather than a Muon (which has opposite mass - lots of mass). In other words, electrons and positrons are only opposites in one characteristic (charge), not as a whole (and in point three below, we see that even this 'opposite' is an illusion).
Secondly, they do not actually cancel each other out, despite the fact that both particles disappear in a collision. If the two particles were truly opposites, then, you could argue that one would have to have negative energy equivalent to the other's positive energy and when they collided the result would be that both disappear and create no photons or other particles. But their collision results in the creation of photons of energy (maintaining the natural principal of preservation of energy). That positron/negatron collisions result in annihilation may be because the charge is an inherent property of these particular leptons, and once the charge is neutralized, the rest of the particle is deconstituted.
We are left with our final option: If these two leptons do have an opposite property (charge), then even though they are not opposite particles, do they still provide us with an example of an opposite property (the electron's negative charge versus the positron's positive one)? Charge can range from various discrete positive values, be neutral, or be negative. If the opposite of a particle with charge is a particle without charge, then, it seems that a positively charged particle could have two opposites - a negatively charged particle, or a particle with no charge. That it has two opposites defeats the idea of saying it has an opposite (which is a linear scale error as defined above).
These three problems can apply to all subatomic particles that I can think of, and all subatomic properties I can think of, including wilder properties such as spin. Rather than say (illogically) that the particles are opposites it is sensible instead to say that some of the properties of the particles interact destructively with each other.
Light and dark are the subjective results of the sensitivity of our eyes to certain wavelengths of electromagnetic radiation (EMR). In every direction, all the time, photons pass us that we cannot perceive with our eyes. In fact we can only see far less than 1% of the range of EMR. So the very idea of "light" and "dark" in human experience is highly anthrocentric and arbitrary. Just because we can't see what's going on doesn't make our idea of an "opposite" something that is rooted in reality. But how about de-humanizing the idea of light and dark and expanding them to cover the entire electromagnetic spectrum? If we proceed to say that "light" is any area of space that you can measure photons coming from, and "dark" is any area where there are none, are these two areas by definition opposite? It turns out that they are not.
Over what timespan would you measure photons? If you just want a snapshot and freeze all of reality, then, no EMR will ever arrive from the direction you're looking in. You can measure the amount of time that passes before an EMR touches your sensor (say, the first one might arrive in 10ms, 20ms, 2000ms or 8000ms etc). But why would a test that receives EMR after 10ms be an 'opposite' to one that receives one after 4000ms? It seems arbitrary, rather than a measure of a true 'opposite'. There is no observed part of the universe from which no photons are ever emitted. It seems that even such an abstract concept of "light" and "dark" falls foul of the complexities of reality. The common-sense approach must be to now admit that calling "dark" and "light" opposites is a traditional aspect of language, but it doesn't reflect anything true about the nature of photons moving through space over time.
“You like a thing to have an opposite. You used to think that God was up on high and I was deep down below [...]; you made him white and me pitchy black (except in Ethiopia where, as Diderot enjoyed pointing out in the Encyclopedie, God was a normal healthy black and I was horribly blanched).”
Good and evil are to many an 'obvious' reality but with thought, the concept of these opposites makes little sense. What is good for one being is frequently bad for another. For example in nature the whole cycle of biological life is based on death and recycling. Hence why major religions have historically been based around these themes, especially vegetation gods who are reborn every Winter Solstice. All predators find it good that prey is available; if you protect the prey you harm the predators, and whilst it is bad from the prey's point of view to be eaten, it is necessary from the predator's point of view. In nature, survival is violent and competitive.
Bacteria4 feed on biological chemicals to survive and breed. What is good for them is bad for us. While antibiotics are good for us and reduce our suffering, their usage creates suffering and death for countless other minor species. What is good for one species is bad for others. While one culture may consider multiple marriage to be a virtue of love and positivity, another considers it an evil sin. What is good in one culture is bad in another. What was good in the Old Testament of the Christian Bible is bad in the New, what is good in the Buddhist Pali scriptures is wrong in the Therevada, what is considered an ethic by one group in society is considered wrong in another. Contraception may be evil according to Catholic doctrine, but, overpopulation causes suffering for all. What the homeless rightly do to survive is a "social evil" to those with homes, and how governments collect tax is evil to the poor person but a social necessity. Good and Evil are impossibly complex, inherently subjective.
Moral subjectivism is not limited to the human concern for other humans. A nuclear attack is bad for billions of people but may well be good for undersea creatures who suffer from our pollutants. Eliminating environmental toxins from our waste may make industry less efficient and slow the economy, but is good for other species. A life-saving vaccine may be good for many people but could be atrocious for the environment and create suffering due to overpopulation.
There are no actions that are "good" or "bad" from the point of view of all peoples, cultures, societies, species and interests. There are no actions that are absolutely good for life, and there are no actions that are bad for all species. There is no "opposite" to good or evil; there is no scale with "good" on one side and "evil" on the other: There are only conflicting subjective interests. It is all personal opinion, compromise and discord. "Good" is not the opposite of "evil" as both concepts are too personal, too subjective and too elusive to warrant definition or resolution as opposites.
Before the rise of Christianity, philosophical thought had moved beyond categorising behaviour as simply virtuous or sinful: Throughout Ethics5 Aristotle places virtues in a table each with two extremes, one of excess, one of deficiency. But they don't form 'opposites' - just scale of each trait. Hence, his thinking in 350BCE was much closer to truth than most popular simplistic schemes are today.
Gay and straight are "opposite" in that they are both different, but not logical opposite. The opposite of any sexuality could easily be asexuality - the attraction to nothing at all. That we choose one sexuality to be the "opposite" of another is nonsense. Gay males are attracted mostly to males, straight males are attracted mostly to females, paedophiles are attracted to children, zoophiles are attracted to animals. Of the multiple sexualities, it makes little sense to say any one is an "opposite" of another except in the most arbitrary way. There are multiple sexualities, on a scale with ill-defined ends, not just two opposing sexualities, gay or straight. It is only by convention that the person who replied "gay and straight" could say as such when I asked him to name two opposites. Convention dictates many opposites - not logic. Conventions set the middle ground about which we invent opposites. In reality, the genes that make up gay or straight are 99% the same in both cases, there is only a finite number, of many thousands, of genes that affect sexuality. That we call one set of genes the "opposite" of another when in fact they are mostly the same is due to a convention that exists in our culture, not because "sexuality" is a integer solid state machine that can be logically paired into opposites. Convention, not logic, dictates what we call "opposite".
The conclusion is that many concepts of "opposites" are illusions. Visible colours such as Black and White are not physical opposites, moral concepts of Good and Evil are anthrocentric and subjectivist. Rich and poor, hot and cold are both only illusionary opposites. In all English usages of the term "opposite" it is an arbitrary and incidental term, according only to cultural definition and suited to Human experience, not to absolute reality. In reality, in science and physics, there are no simple opposites. Physically it is not true that "everything has an opposite" and truer that "nothing has an opposite". Beyond suppositions and assumption, any in-depth investigation of an "opposite" shows it to be a useful phrase and term, but not a description of any deep reality. The term "opposite" is only suited to English and art, not to logical philosophy or physical science.
All things are connected, therefore nothing has a true opposite.
If many of the arguments on this page are purely rhetorical, it is because the basis of "opposites" it itself rhetorical, arbitrary and illusionary. Convention and assumption rule what we call "opposites", in reality there are none that turn out to be genuinely opposite without making assumptions about central points.