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Many examples of this fallacy I can think of are committed when trying to reason about diagnosis and cause of diseases.

When someone has AIDS, people jump to the conclusion that he had unprotected sex or he is on drugs (same for smoking...etc).

It is obvious that these conclusions are generally built on an affirming the consequent fallacy. Because if we were to translate it into propositional logic, we would have

  • Premise 1 : If SMOKING then HEALTH-PROBLEMS
  • Premise 2 : HEALTH-PROBLEMS
  • Conclusion : Therefore, SMOKING

As you can see, the first premise is true (assuming that HEALTH-PROBLEMS here means anything that is linked to smoking, even coughing).

It is not the case that anyone who is coughing, or having lung disease is necessarily smoking, and yet people assume that one is smoking if one has lung cancer, or conclude that one has had unprotected sex if one has AIDS.

So, from this perspective, it is an affirming the consequent.

Note : Of course we cannot consider it an affirming the consequent if the argument were of this form :

  • Premise 1 : If HEALTH-PROBLEMS then SMOKING
  • Premise 2 : HEALTH-PROBLEMS
  • Conclusion : Therefore, SMOKING

If someone concludes that one is smoking following the previous form of reasoning, then it is not an affirming the consequent, but rather a valid Modus Ponens.

Although it is valid, in this case the first premise is false, since HEALTH-PROBLEMS does not necessarily imply SMOKING.

So, this type of reasoning about disease problems is generally built on:

  • AAn confirmingaffirming the consequent fallacy (with the conditional being true)
  • Or, a valid Modus Ponens (with the conditional being false).

Most of these arguments are either valid with a false premise, or invalid with a true premise.

Except for the cases where a disease is caused by one and only one factor (which is very rare).

Many examples of this fallacy I can think of are committed when trying to reason about diagnosis and cause of diseases.

When someone has AIDS, people jump to the conclusion that he had unprotected sex or he is on drugs (same for smoking...etc).

It is obvious that these conclusions are generally built on an affirming the consequent fallacy. Because if we were to translate it into propositional logic, we would have

  • Premise 1 : If SMOKING then HEALTH-PROBLEMS
  • Premise 2 : HEALTH-PROBLEMS
  • Conclusion : Therefore, SMOKING

As you can see, the first premise is true (assuming that HEALTH-PROBLEMS here means anything that is linked to smoking, even coughing).

It is not the case that anyone who is coughing, or having lung disease is necessarily smoking, and yet people assume that one is smoking if one has lung cancer, or conclude that one has had unprotected sex if one has AIDS.

So, from this perspective, it is an affirming the consequent.

Note : Of course we cannot consider it an affirming the consequent if the argument were of this form :

  • Premise 1 : If HEALTH-PROBLEMS then SMOKING
  • Premise 2 : HEALTH-PROBLEMS
  • Conclusion : Therefore, SMOKING

If someone concludes that one is smoking following the previous form of reasoning, then it is not an affirming the consequent, but rather a valid Modus Ponens.

Although it is valid, in this case the first premise is false, since HEALTH-PROBLEMS does not necessarily imply SMOKING.

So, this type of reasoning about disease problems is generally built on:

  • A confirming the consequent fallacy (with the conditional being true)
  • Or, a valid Modus Ponens (with the conditional being false).

Most of these arguments are either valid with a false premise, or invalid with a true premise.

Except for the cases where a disease is caused by one and only one factor (which is very rare).

Many examples of this fallacy I can think of are committed when trying to reason about diagnosis and cause of diseases.

When someone has AIDS, people jump to the conclusion that he had unprotected sex or he is on drugs (same for smoking...etc).

It is obvious that these conclusions are generally built on an affirming the consequent fallacy. Because if we were to translate it into propositional logic, we would have

  • Premise 1 : If SMOKING then HEALTH-PROBLEMS
  • Premise 2 : HEALTH-PROBLEMS
  • Conclusion : Therefore, SMOKING

As you can see, the first premise is true (assuming that HEALTH-PROBLEMS here means anything that is linked to smoking, even coughing).

It is not the case that anyone who is coughing, or having lung disease is necessarily smoking, and yet people assume that one is smoking if one has lung cancer, or conclude that one has had unprotected sex if one has AIDS.

So, from this perspective, it is an affirming the consequent.

Note : Of course we cannot consider it an affirming the consequent if the argument were of this form :

  • Premise 1 : If HEALTH-PROBLEMS then SMOKING
  • Premise 2 : HEALTH-PROBLEMS
  • Conclusion : Therefore, SMOKING

If someone concludes that one is smoking following the previous form of reasoning, then it is not an affirming the consequent, but rather a valid Modus Ponens.

Although it is valid, in this case the first premise is false, since HEALTH-PROBLEMS does not necessarily imply SMOKING.

So, this type of reasoning about disease problems is generally built on:

  • An affirming the consequent fallacy (with the conditional being true)
  • Or, a valid Modus Ponens (with the conditional being false).

Most of these arguments are either valid with a false premise, or invalid with a true premise.

Except for the cases where a disease is caused by one and only one factor (which is very rare).

1
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Many examples of this fallacy I can think of are committed when trying to reason about diagnosis and cause of diseases.

When someone has AIDS, people jump to the conclusion that he had unprotected sex or he is on drugs (same for smoking...etc).

It is obvious that these conclusions are generally built on an affirming the consequent fallacy. Because if we were to translate it into propositional logic, we would have

  • Premise 1 : If SMOKING then HEALTH-PROBLEMS
  • Premise 2 : HEALTH-PROBLEMS
  • Conclusion : Therefore, SMOKING

As you can see, the first premise is true (assuming that HEALTH-PROBLEMS here means anything that is linked to smoking, even coughing).

It is not the case that anyone who is coughing, or having lung disease is necessarily smoking, and yet people assume that one is smoking if one has lung cancer, or conclude that one has had unprotected sex if one has AIDS.

So, from this perspective, it is an affirming the consequent.

Note : Of course we cannot consider it an affirming the consequent if the argument were of this form :

  • Premise 1 : If HEALTH-PROBLEMS then SMOKING
  • Premise 2 : HEALTH-PROBLEMS
  • Conclusion : Therefore, SMOKING

If someone concludes that one is smoking following the previous form of reasoning, then it is not an affirming the consequent, but rather a valid Modus Ponens.

Although it is valid, in this case the first premise is false, since HEALTH-PROBLEMS does not necessarily imply SMOKING.

So, this type of reasoning about disease problems is generally built on:

  • A confirming the consequent fallacy (with the conditional being true)
  • Or, a valid Modus Ponens (with the conditional being false).

Most of these arguments are either valid with a false premise, or invalid with a true premise.

Except for the cases where a disease is caused by one and only one factor (which is very rare).