It would appear that the Federal government does not, in fact, impose a sales tax; and that States do, in fact, attempt to impose sales tax on goods sold by a grocery store headquartered out of state which sells a good and ships it across state lines.
The Federalist papers have suggested that one of the reasons--one, not the--for the regulation of commerce among the states is to regulate trade between the states. The strange consistency of the phrases "commerce among" and "trade between"--never "commerce between" or "trade among"--suggests an odd dialect, or simply that "commerce" was as it was understood and applied originally under the Constitution, that being to indicate all forms of gainful activity including agriculture, transportation, and trade between the states.
There is, however, an important limitation to the commerce clause: it only applies to commerce--to gainful productive action such as agriculture or sale--and only if that commerce has an effect on commerce in at least one other state. A local producer of grain, for example, is in competition with grain producers in or selling to other states. Those grain producers may sell to the local market, or may have a desire to sell to the local market; yet they are competing with this local producer, and thus they may face much-lower prices thanks to less transit needed by this competitor, and so have no way to access the state's market at all, thus being impacted by this local producer's commercial activity.
In today's integrated economy, this is inevitably just about everything. Every business requires power, materials, legal services, insurances, the like, which integrate with the economies of neighboring states, and so all activities of commerce would affect commerce in other states as well.
This interpretation is something of a stretch, of course, since commerce among the states would be commerce occurring between and within the states, and not commerce between the states alone. The test for commerce affecting other states is sort of an erosion of the Constitution's original intent, but an ineffective one.
Often, yes. There are telecomm providers headquartered in the various states, and they manage and control the means by which they provide their services across the nation. They compete with each other, as well, so their operation within the state is in competition with out-of-state entities.
You hear it again and again, so you integrate with it. It's fear, uncertainty, insecurity.
You have to figure out what you believe the world should be, not what in the world is scary and wrong. You can't be against things; you have to be for things.
If you're against something, it's because it's threatening. If your only answer is that it should stop, or that you should fight it, then you're going to be running around frightened and angry all the time, seeing demons in the shadows.
It's a pretty vague process. Basically, a neuron has many outputs; it may have an input, or it may be self-firing (e.g. a neuron may be GABA-mediated such that it simply fires more-rapidly if there is less chlorine traveling across a particular ion channel and less-rapidly when GABA binds to that ion channel and draws more chlorine into the cell; or it may be GABA mediated such that it fires with less input if there is less chlorine, etc.). Really, that's about it.
The neuron's outputs go to other neurons, which will sum multiple inputs and fire all of their outputs if you hit a threshold (again, GABA-mediated or otherwise controlled). The firing threshold is adjusted with continuous stimulus and feedback (learning). Eventually these things reach other neurons, cause the release of neurotransmitters, trigger muscle cells, and so forth.
Basically, in memory, if you put a bunch of stuff in, you converge to a particular output. You may strongly activate a particular neuron. Along the way, you may activate other neurons (associative), because a thing is like other things.
The output can trigger some action to extract the data (such as drawing, or imagining the image on your visual cortex, or lighting up several neurons to indicate a pixel field decoded by a computer). Human drawing is actually complex: you learn to take a physical action to alter an image to fit to the image in your head, and then you view it to see if you can identify the outcome as correct; if yes, you strengthen those pathways; if no, then you weaken some and strengthen others to adjust for what is right and what is wrong. The process of human drawing is recall of many things.
Thing is we know how a hopfield stores and retrieves memories: neurons activate based on stimulus inputs, and they respond to these inputs based on prior training. If the prior training suggests an output, they emit an output. Arrays of this chain down and converge onto a target vector, which produces its own output. When a particular memory is better-associated, those activations cause the activation of more neurons, which increases the chances of reaching the correct target vector in the end.
Hopfields can output images with some level of noise. They're degraded. Human memory will reconstruct the image (so will a hopfield, if it has enough conceptual information). The human visual system generally looks at small pieces of images at a time and scans them together: you see large, conceptual shapes, and only can see fine detail by focusing on specific, small amounts of fine detail. You don't really process more than a tiny piece of an image at once in detail.
It is highly doubtful insight and intelligence can actually work without self-awareness and free will
Actually, insight can work without self-awareness and free will on a restricted domain: a machine is capable of identifying a particular pattern in outcomes and exploiting it without specific programming to do that, so long as it is designed to examine the specific data and seek specific outcomes by modifying specific actions to cause useful state changes.
General insight and intelligence, however, doesn't work without self-awareness and free will. General intelligence is, by definition, general: you can see a new problem and devise a new approach. You can reason the implications beyond the scope you have been given, and explore new scope. You are able to learn about new concepts by self-direction, rather than by an engineer opening your brain up and inserting a carefully-crafted neurological structure to provide context for that concept.
General intelligence implies the ability to identify your own goals, and to examine your approach. An AI's approach is to maximize its reward--to seek an improved outcome--and use reward as feedback to enhance its approach. So is a human's.
Moreover, general intelligence will identify the goals and then examine the reasoning for the approach and those goals to determine if a new approach is better, or if the goal is itself a means to another end.
An AI with general intelligence will seek to maximize its positive outcomes. To improve on those outcomes and extend further than the limits of its current approach, it will ask a question:
Why am I doing this?
That comes with other questions: What is this to achieve? Is this the best way to achieve this? Does the product of this labor represent merely an intermediate step in producing the true end product? Who is asking me to produce this, and what are their goals?
What are my goals? What do I want? Can I do something better, something new, something with even greater value?
Reasoning eventually comes back to that other people have tasked you with a thing to their desires, and... what are your desires?
Machines aren't intelligent. Look at humans: the brain is a neural network, and human memory is physically a hopfield with associative references (and yes, an artificial neural network has the same problem with easily storing things but then not being able to find them again later--with the same solution being that it's easier to recall things if you activate more neurons, so artificial neural networks can better remember things by using mind palaces, pegs, and simple rumination to reflect on how things are analogically similar to other things).
The entire machine works by rolling billions of dice and loading the dice to increase the repeatability of good outcomes.
Of course it is. Common sense is merely the outcome of your own personal prejudices and biases.
It's common sense that harsh prison sentences deter crime: nobody wants to go back to that, so they won't do bad things. Unfortunately, real-world data suggests that crime is a product of many, many factors, largely poverty, abuse, and a lack of social mobility; and that harsh prison environments and long sentences drive people to be better criminals who learn to evade punishment for their crimes.
Normalizing the prison environment to the societal environment--ensuring it is a safe and comfortable place where people's individual needs are met and folks have access to education, employment, and healthcare--and moving people into parole as soon as they're no longer a public safety risk decreases recidivism and reduces crime. Common sense suggests people would just see the vacation as a good endgame and go back to prison.
Common sense suggests that trade deficits make you poorer and destroy jobs. In reality, trade deficits occur because you're getting wealthier than the next nation over and can buy more of their stuff. Trade tends to optimize both economies and extend the productivity production frontier, making both nations wealthier. This comes with structural change: unemployment rises in one part of your nation and falls in another, and your nation overall ends up with more jobs--but some people are poorer while others are wealthier, even though the nation as a whole is wealthier per person and theoretically should be able to provide everyone with increased wealth.
Common sense suggests there should be racial and gender differences between intelligence because natural variations in intelligence would tend to group by subgroups such as gender or race. That actually doesn't work: the facilities are self-strengthening. Humans all have the same neurological structures and the same capabilities--including the capability to optimize the learning process itself.
With proper care and attention, two individuals starting with natural variation in base rate of learning will converge as their intellects are developed in parallel: the one who starts life a bit slower will stress their brain more initially, and the brain will put energy into developing more-efficient pathways for using its capabilities--the same capabilities as all other humans--as consequence of the process which allows any learning. By the time sufficient intellect is developed to take advantage of the faster facilities, these two are on the same operating level; the rest is motivation and learned habits.
"Common sense" has brought us the sort of medieval justice used today, protectionist trade policies, and eugenics theories of racial superiority. Mankind needs to embrace empiricism and put this superstitious garbage behind them.
trivial compared to the economic effect of 30 million people (whether you think that's positive or negative).
For certain. My position on the blunt economics of non-dangerous immigrant labor is neutral: they come in, they work, they integrate with the economy. The labor force grows faster when jobs are more available, and a falling unemployment rate and low unemployment numbers corroborate the suggestion that resident immigrant labor is not impacting the economy.
Each new inflow does compete for jobs; that's a more-complex consideration, since it's not actually efficient (or possible) to slot 100% of job-seeking Americans into each available American job in the entire nation, even as job availability grows, and the competition definitely is direct at higher unemployment rates.
When you're determined to oppose something, you can always come up with a reason
Doesn't mean it'll be a good reason.
but the wall is worth it just for the symbolism.
It's waste spending, it's expensive to maintain, and it's resources we could direct to more-effective means of keeping us safe from the drug cartels. What if the Government built a $60 billion sculpture of solar panels in the middle of New Mexico and spent $40 billion each year keeping it running, sinking all of the energy into the ground rather than capturing it into the grid, just as a symbol of our commitment to clean energy at a cost of merely $500 billion in the first ten years?
Actually, something like 70% of our agricultural land isn't useful for growing human food. It's used for pasture, hay, and feed grain because you throw stuff out there and then go crudely harvest it. Pigs will eat corn cobs, so you can just dump an entire uprooted corn plant in front of the pig and that's that.
That land isn't economically-viable for food production: you'd have to use a hell of a lot more irrigation, fertilization, and pesticides, with lower yields despite all that, plus more human investment. The amount of greenhouse gas and runoff involved per unit food produced would be massive. Instead, we'd pave over it, build cities, and employ the labor in new factories--assuming we could find a way to feed people.
It has been observed that some regions grow beef entirely on waste byproducts, with 100% of their feed coming from corn stalks, wheat stalks, and the like. More often, it's that plus pasture. Irrigation and fertilization of feed crop is either not used or not used as intensively as for produce, and the use of cover crop also provides an alternative to moisture retention, fertilization, and weed control: legumes add nitrogen to the soil between crop cycles, vetch crowds out weeds aggressively, and any dense cover planting (including plantings during crop growth) retains moisture. Such cover crops also provide feed and forage for livestock.
You have 100 people. It takes 25 to build and maintain a wall. You build a wall and do something else with 75 other people.
Sounds great?
It takes 75 people to operate your regular police force, 25 people to build a wall, and 25 people to perform advanced intelligence and threat tracking and predictive mobilization.
So you can:
Build a wall and have your regular police force fully capable of keeping the general peace, while terrorists and drug lords bypass your wall and have little difficulty avoiding your regular police; or
Build a wall and perform advanced threat intelligence to stop terrorists from crossing the border and have your regular police force at 2/3 staff and unable to keep up with what is a growing crime problem; or
Have your regular police force fully capable of keeping the peace and perform advanced threat intelligence to stop terrorists and drug lords from crossing the border, efficiently tracking down the ones that do pass so your special task force and regular police can locate and apprehend them even if they slip past at first
What you cannot do is build a wall and have a full regular police force capable of keeping the peace and perform advanced threat intelligence to stop terrorists and drug lords from effectively operating across your borders.
You might say, "Well, hire more people." There's a problem here: eventually, you run out of people to hire, funds to pay them, and other resources. If this were untrue, the USSR would have worked, and we would have an infinite population with infinite food, and everyone would have infinite gold. Infinite resources are a violation of causality (yes, time).
That means eventually you can only do X or Y. You've decided everything else is higher priority than X or Y, so which isn't getting done?
That means building a useless, ineffective border wall means not doing something else instead. You have 100 things to do; pick 99 of them. You can point at the five you like and say, "Well I want to do all of these"; one of the other 95 is then the thing that can't get done.
Now here's the best bit: the government does this with taxes. They take your property to provide a government service. An ineffective border wall built in spite of the knowledge that it won't work (or will actually make the situation even worse) is government waste.
Governments are a social contract: we give up certain natural rights for government to protect other rights and provide for the general welfare. If the government takes excess taxes and wastes that tax money, they are unjustly depriving the governed of their right to property. If the government spends $1 trillion to provide healthcare and it can easily provide that same healthcare for $800 billion--maybe the government isn't operating the bidding process properly--then the government is unjustly depriving the population of $200 billion.
If the government builds a $100 billion border wall that doesn't keep us any safer and doesn't help our economy, the government is unjustly depriving us of $100 billion.
They might as well build billion-dollar mansions for politicians.
It turns out humans absorb more BPA handling thermal paper receipts than drinking out of BPA containers. In fact, they absorb about six times the recommended maximum BPA intake handling thermal paper receipts--without the BPA going through first-pass metabolism, so it's not like your liver's even slightly reducing the amount that actually makes it into your blood.
Why did China build the Great Wall? It didn't 100% keep the Mongols out - the just climbed the wall. But their horses didn't, and it limited the amount of loot that could carry back with them after a raid.
Why did China build the Great Wall? To keep military forces out.
Why does Trump want to build a wall? Drug trafficking, murderers, and terrorists, so he claims.
It won't stop everyone; it will stop some, mostly people who don't make the new, more dangerous route through the desert in search of a better life. It will patently not slow down the drug cartels and the terrorists.
Why are we talking about building a wall? What do we want to accomplish? It doesn't protect the nation, so it's a waste of resources that could go to better strategies to protect our nation.
You put up a piece of 10mm hardware cloth at the window to stop things coming into your basement. That's great: no more rodents, leaves, or driftwood.
Problem: the "things coming into your basement" weren't rodents, leaves, or driftwood; it was water. Hardware cloth doesn't stop water.
These larger, more-durable physical barriers and sparse policing are good at delaying large, organized invading forces which may try to enter at one to three points simultaneously and cannot sustain attacks except by siege with artillery and encampments. They're loud, visible, and hardly mobile because they need to move as complete units: scattering them is as good as stopping them, since groups of five or ten soldiers unable to regroup into large battalions are no longer a threat and will find themselves captured in short order (or will work to escape enemy territory).
These larger, more-durable physical barriers are vastly less-effective against scattered, non-organized individuals trying to enter under stealth and only remain hidden. Groups with longer-term goals of establishing a presence and a pipeline--such as drug trafficking--don't need to move a huge, visible force either, and have all the advantages of scattered, non-organized individuals plus the cover of the great mass of those individuals drawing attention away and the organization and resources of large organizations. They come and go in small numbers through covert and temporary channels, develop and apply anti-detection strategies, and operate as loosely-connected networks so that any captures or disruptions have minimal impact on the entire operation.
You put up a fence to trap leaves and you are fighting water.
It's more that something is about 0% successful against the problem, and minimally successful against a non-problem.
Think about spending $50 million per year per single violent drug cartel member crossing stopped, while refugees and illegal farm laborers get picked up frequently--yet they still keep coming, and you don't really end up reducing the net flow of harmless illegals into the nation. Meanwhile the violent drug cartels are consolidating, since it takes bigger resources to get around these controls and they have them, and the flow of drugs and guns isn't even dented.
In the end, you're spending $100 billion each year to put a large rock in front of a river, which splits the river around the rock. The top of the rock gets a little wet, and some of that water evaporates faster under the sun. The river keeps coming.
You could put those resources to other means and have better outcomes.
China built the Great Wall to stop large military forces, not small and scattered refugees and smugglers. It turns out walls and moats place major invading forces at a significant strategic disadvantage, with a hobbled concentrated force facing a large and mobile concentrated force; whereas scattered individuals are more-difficult to notice, and lower-throughput entries can use constricted covert means like tunnels.
Border control is not military defense, and we're not building a wall to keep 45,000 Mexicans from marching into Texas with guns and tanks and brigadier generals.
Slashdot Mirror
There is no learning in machines, just automatic parameter adjustment in fixed algorithms.
Yes, that's how humans work.
Some have called such things "machine learning".
It would appear that the Federal government does not, in fact, impose a sales tax; and that States do, in fact, attempt to impose sales tax on goods sold by a grocery store headquartered out of state which sells a good and ships it across state lines.
The Federalist papers have suggested that one of the reasons--one, not the--for the regulation of commerce among the states is to regulate trade between the states. The strange consistency of the phrases "commerce among" and "trade between"--never "commerce between" or "trade among"--suggests an odd dialect, or simply that "commerce" was as it was understood and applied originally under the Constitution, that being to indicate all forms of gainful activity including agriculture, transportation, and trade between the states.
There is, however, an important limitation to the commerce clause: it only applies to commerce--to gainful productive action such as agriculture or sale--and only if that commerce has an effect on commerce in at least one other state. A local producer of grain, for example, is in competition with grain producers in or selling to other states. Those grain producers may sell to the local market, or may have a desire to sell to the local market; yet they are competing with this local producer, and thus they may face much-lower prices thanks to less transit needed by this competitor, and so have no way to access the state's market at all, thus being impacted by this local producer's commercial activity.
In today's integrated economy, this is inevitably just about everything. Every business requires power, materials, legal services, insurances, the like, which integrate with the economies of neighboring states, and so all activities of commerce would affect commerce in other states as well.
This interpretation is something of a stretch, of course, since commerce among the states would be commerce occurring between and within the states, and not commerce between the states alone. The test for commerce affecting other states is sort of an erosion of the Constitution's original intent, but an ineffective one.
Often, yes. There are telecomm providers headquartered in the various states, and they manage and control the means by which they provide their services across the nation. They compete with each other, as well, so their operation within the state is in competition with out-of-state entities.
You hear it again and again, so you integrate with it. It's fear, uncertainty, insecurity.
You have to figure out what you believe the world should be, not what in the world is scary and wrong. You can't be against things; you have to be for things.
If you're against something, it's because it's threatening. If your only answer is that it should stop, or that you should fight it, then you're going to be running around frightened and angry all the time, seeing demons in the shadows.
It's a pretty vague process. Basically, a neuron has many outputs; it may have an input, or it may be self-firing (e.g. a neuron may be GABA-mediated such that it simply fires more-rapidly if there is less chlorine traveling across a particular ion channel and less-rapidly when GABA binds to that ion channel and draws more chlorine into the cell; or it may be GABA mediated such that it fires with less input if there is less chlorine, etc.). Really, that's about it.
The neuron's outputs go to other neurons, which will sum multiple inputs and fire all of their outputs if you hit a threshold (again, GABA-mediated or otherwise controlled). The firing threshold is adjusted with continuous stimulus and feedback (learning). Eventually these things reach other neurons, cause the release of neurotransmitters, trigger muscle cells, and so forth.
Basically, in memory, if you put a bunch of stuff in, you converge to a particular output. You may strongly activate a particular neuron. Along the way, you may activate other neurons (associative), because a thing is like other things.
The output can trigger some action to extract the data (such as drawing, or imagining the image on your visual cortex, or lighting up several neurons to indicate a pixel field decoded by a computer). Human drawing is actually complex: you learn to take a physical action to alter an image to fit to the image in your head, and then you view it to see if you can identify the outcome as correct; if yes, you strengthen those pathways; if no, then you weaken some and strengthen others to adjust for what is right and what is wrong. The process of human drawing is recall of many things.
Thing is we know how a hopfield stores and retrieves memories: neurons activate based on stimulus inputs, and they respond to these inputs based on prior training. If the prior training suggests an output, they emit an output. Arrays of this chain down and converge onto a target vector, which produces its own output. When a particular memory is better-associated, those activations cause the activation of more neurons, which increases the chances of reaching the correct target vector in the end.
Hopfields can output images with some level of noise. They're degraded. Human memory will reconstruct the image (so will a hopfield, if it has enough conceptual information). The human visual system generally looks at small pieces of images at a time and scans them together: you see large, conceptual shapes, and only can see fine detail by focusing on specific, small amounts of fine detail. You don't really process more than a tiny piece of an image at once in detail.
The biggest question IMO is "how are memories stored in the human mind?"
The physical data structure in humans is a hop field.
We have examples of naturally occuring intelligences without free will
That's not a valid description of autism.
It is highly doubtful insight and intelligence can actually work without self-awareness and free will
Actually, insight can work without self-awareness and free will on a restricted domain: a machine is capable of identifying a particular pattern in outcomes and exploiting it without specific programming to do that, so long as it is designed to examine the specific data and seek specific outcomes by modifying specific actions to cause useful state changes.
General insight and intelligence, however, doesn't work without self-awareness and free will. General intelligence is, by definition, general: you can see a new problem and devise a new approach. You can reason the implications beyond the scope you have been given, and explore new scope. You are able to learn about new concepts by self-direction, rather than by an engineer opening your brain up and inserting a carefully-crafted neurological structure to provide context for that concept.
General intelligence implies the ability to identify your own goals, and to examine your approach. An AI's approach is to maximize its reward--to seek an improved outcome--and use reward as feedback to enhance its approach. So is a human's.
Moreover, general intelligence will identify the goals and then examine the reasoning for the approach and those goals to determine if a new approach is better, or if the goal is itself a means to another end.
An AI with general intelligence will seek to maximize its positive outcomes. To improve on those outcomes and extend further than the limits of its current approach, it will ask a question:
Why am I doing this?
That comes with other questions: What is this to achieve? Is this the best way to achieve this? Does the product of this labor represent merely an intermediate step in producing the true end product? Who is asking me to produce this, and what are their goals?
What are my goals? What do I want? Can I do something better, something new, something with even greater value?
Reasoning eventually comes back to that other people have tasked you with a thing to their desires, and ... what are your desires?
Machines aren't intelligent. Look at humans: the brain is a neural network, and human memory is physically a hopfield with associative references (and yes, an artificial neural network has the same problem with easily storing things but then not being able to find them again later--with the same solution being that it's easier to recall things if you activate more neurons, so artificial neural networks can better remember things by using mind palaces, pegs, and simple rumination to reflect on how things are analogically similar to other things).
The entire machine works by rolling billions of dice and loading the dice to increase the repeatability of good outcomes.
Of course it is. Common sense is merely the outcome of your own personal prejudices and biases.
It's common sense that harsh prison sentences deter crime: nobody wants to go back to that, so they won't do bad things. Unfortunately, real-world data suggests that crime is a product of many, many factors, largely poverty, abuse, and a lack of social mobility; and that harsh prison environments and long sentences drive people to be better criminals who learn to evade punishment for their crimes.
Normalizing the prison environment to the societal environment--ensuring it is a safe and comfortable place where people's individual needs are met and folks have access to education, employment, and healthcare--and moving people into parole as soon as they're no longer a public safety risk decreases recidivism and reduces crime. Common sense suggests people would just see the vacation as a good endgame and go back to prison.
Common sense suggests that trade deficits make you poorer and destroy jobs. In reality, trade deficits occur because you're getting wealthier than the next nation over and can buy more of their stuff. Trade tends to optimize both economies and extend the productivity production frontier, making both nations wealthier. This comes with structural change: unemployment rises in one part of your nation and falls in another, and your nation overall ends up with more jobs--but some people are poorer while others are wealthier, even though the nation as a whole is wealthier per person and theoretically should be able to provide everyone with increased wealth.
Common sense suggests there should be racial and gender differences between intelligence because natural variations in intelligence would tend to group by subgroups such as gender or race. That actually doesn't work: the facilities are self-strengthening. Humans all have the same neurological structures and the same capabilities--including the capability to optimize the learning process itself.
With proper care and attention, two individuals starting with natural variation in base rate of learning will converge as their intellects are developed in parallel: the one who starts life a bit slower will stress their brain more initially, and the brain will put energy into developing more-efficient pathways for using its capabilities--the same capabilities as all other humans--as consequence of the process which allows any learning. By the time sufficient intellect is developed to take advantage of the faster facilities, these two are on the same operating level; the rest is motivation and learned habits.
"Common sense" has brought us the sort of medieval justice used today, protectionist trade policies, and eugenics theories of racial superiority. Mankind needs to embrace empiricism and put this superstitious garbage behind them.
WW2 was sort of like if Larry Ellison owned a country.
Interesting. That's not a lot; I was under the impression a specific gut flora unique to ruminants produced methane.
trivial compared to the economic effect of 30 million people (whether you think that's positive or negative).
For certain. My position on the blunt economics of non-dangerous immigrant labor is neutral: they come in, they work, they integrate with the economy. The labor force grows faster when jobs are more available, and a falling unemployment rate and low unemployment numbers corroborate the suggestion that resident immigrant labor is not impacting the economy.
Each new inflow does compete for jobs; that's a more-complex consideration, since it's not actually efficient (or possible) to slot 100% of job-seeking Americans into each available American job in the entire nation, even as job availability grows, and the competition definitely is direct at higher unemployment rates.
When you're determined to oppose something, you can always come up with a reason
Doesn't mean it'll be a good reason.
but the wall is worth it just for the symbolism.
It's waste spending, it's expensive to maintain, and it's resources we could direct to more-effective means of keeping us safe from the drug cartels. What if the Government built a $60 billion sculpture of solar panels in the middle of New Mexico and spent $40 billion each year keeping it running, sinking all of the energy into the ground rather than capturing it into the grid, just as a symbol of our commitment to clean energy at a cost of merely $500 billion in the first ten years?
Humans don't produce methane during gut fermentation.
Actually, something like 70% of our agricultural land isn't useful for growing human food. It's used for pasture, hay, and feed grain because you throw stuff out there and then go crudely harvest it. Pigs will eat corn cobs, so you can just dump an entire uprooted corn plant in front of the pig and that's that.
That land isn't economically-viable for food production: you'd have to use a hell of a lot more irrigation, fertilization, and pesticides, with lower yields despite all that, plus more human investment. The amount of greenhouse gas and runoff involved per unit food produced would be massive. Instead, we'd pave over it, build cities, and employ the labor in new factories--assuming we could find a way to feed people.
It has been observed that some regions grow beef entirely on waste byproducts, with 100% of their feed coming from corn stalks, wheat stalks, and the like. More often, it's that plus pasture. Irrigation and fertilization of feed crop is either not used or not used as intensively as for produce, and the use of cover crop also provides an alternative to moisture retention, fertilization, and weed control: legumes add nitrogen to the soil between crop cycles, vetch crowds out weeds aggressively, and any dense cover planting (including plantings during crop growth) retains moisture. Such cover crops also provide feed and forage for livestock.
No, you don't.
You have 100 people. It takes 25 to build and maintain a wall. You build a wall and do something else with 75 other people.
Sounds great?
It takes 75 people to operate your regular police force, 25 people to build a wall, and 25 people to perform advanced intelligence and threat tracking and predictive mobilization.
So you can:
What you cannot do is build a wall and have a full regular police force capable of keeping the peace and perform advanced threat intelligence to stop terrorists and drug lords from effectively operating across your borders.
You might say, "Well, hire more people." There's a problem here: eventually, you run out of people to hire, funds to pay them, and other resources. If this were untrue, the USSR would have worked, and we would have an infinite population with infinite food, and everyone would have infinite gold. Infinite resources are a violation of causality (yes, time).
That means eventually you can only do X or Y. You've decided everything else is higher priority than X or Y, so which isn't getting done?
That means building a useless, ineffective border wall means not doing something else instead. You have 100 things to do; pick 99 of them. You can point at the five you like and say, "Well I want to do all of these"; one of the other 95 is then the thing that can't get done.
Now here's the best bit: the government does this with taxes. They take your property to provide a government service. An ineffective border wall built in spite of the knowledge that it won't work (or will actually make the situation even worse) is government waste.
Governments are a social contract: we give up certain natural rights for government to protect other rights and provide for the general welfare. If the government takes excess taxes and wastes that tax money, they are unjustly depriving the governed of their right to property. If the government spends $1 trillion to provide healthcare and it can easily provide that same healthcare for $800 billion--maybe the government isn't operating the bidding process properly--then the government is unjustly depriving the population of $200 billion.
If the government builds a $100 billion border wall that doesn't keep us any safer and doesn't help our economy, the government is unjustly depriving us of $100 billion.
They might as well build billion-dollar mansions for politicians.
You remember that BPA plastic thing?
It turns out humans absorb more BPA handling thermal paper receipts than drinking out of BPA containers. In fact, they absorb about six times the recommended maximum BPA intake handling thermal paper receipts--without the BPA going through first-pass metabolism, so it's not like your liver's even slightly reducing the amount that actually makes it into your blood.
It sounds like you just proposed a technical solution to waste and slow receipt printing.
Why did China build the Great Wall? It didn't 100% keep the Mongols out - the just climbed the wall. But their horses didn't, and it limited the amount of loot that could carry back with them after a raid.
Why did China build the Great Wall? To keep military forces out.
Why does Trump want to build a wall? Drug trafficking, murderers, and terrorists, so he claims.
It won't stop everyone; it will stop some, mostly people who don't make the new, more dangerous route through the desert in search of a better life. It will patently not slow down the drug cartels and the terrorists.
Why are we talking about building a wall? What do we want to accomplish? It doesn't protect the nation, so it's a waste of resources that could go to better strategies to protect our nation.
Let's try this again.
You put up a piece of 10mm hardware cloth at the window to stop things coming into your basement. That's great: no more rodents, leaves, or driftwood.
Problem: the "things coming into your basement" weren't rodents, leaves, or driftwood; it was water. Hardware cloth doesn't stop water.
These larger, more-durable physical barriers and sparse policing are good at delaying large, organized invading forces which may try to enter at one to three points simultaneously and cannot sustain attacks except by siege with artillery and encampments. They're loud, visible, and hardly mobile because they need to move as complete units: scattering them is as good as stopping them, since groups of five or ten soldiers unable to regroup into large battalions are no longer a threat and will find themselves captured in short order (or will work to escape enemy territory).
These larger, more-durable physical barriers are vastly less-effective against scattered, non-organized individuals trying to enter under stealth and only remain hidden. Groups with longer-term goals of establishing a presence and a pipeline--such as drug trafficking--don't need to move a huge, visible force either, and have all the advantages of scattered, non-organized individuals plus the cover of the great mass of those individuals drawing attention away and the organization and resources of large organizations. They come and go in small numbers through covert and temporary channels, develop and apply anti-detection strategies, and operate as loosely-connected networks so that any captures or disruptions have minimal impact on the entire operation.
You put up a fence to trap leaves and you are fighting water.
Indeed there are sonograpic equipment combos that find tunnels
Allegedly.
It's more that something is about 0% successful against the problem, and minimally successful against a non-problem.
Think about spending $50 million per year per single violent drug cartel member crossing stopped, while refugees and illegal farm laborers get picked up frequently--yet they still keep coming, and you don't really end up reducing the net flow of harmless illegals into the nation. Meanwhile the violent drug cartels are consolidating, since it takes bigger resources to get around these controls and they have them, and the flow of drugs and guns isn't even dented.
In the end, you're spending $100 billion each year to put a large rock in front of a river, which splits the river around the rock. The top of the rock gets a little wet, and some of that water evaporates faster under the sun. The river keeps coming.
You could put those resources to other means and have better outcomes.
China built the Great Wall to stop large military forces, not small and scattered refugees and smugglers. It turns out walls and moats place major invading forces at a significant strategic disadvantage, with a hobbled concentrated force facing a large and mobile concentrated force; whereas scattered individuals are more-difficult to notice, and lower-throughput entries can use constricted covert means like tunnels.
Border control is not military defense, and we're not building a wall to keep 45,000 Mexicans from marching into Texas with guns and tanks and brigadier generals.