Logical Fallacies in Advertising – Analysing Patterns of Rhetoric

Toulmin analysis is an efficient and powerful tool to assess the validity of arguments. As a PhD student in marketing and a philosopher, I have an ambivalent relationship with the promotional aspect of business.

As a philosopher, I am used to using methods such as the Toulmin Analysis to examine arguments, but in advertising, logic is usually not important. There are many logical fallacies in advertising, not because the designers of the communication lack skills in logical reasoning but because they try to convince the viewer outside of logic.

One of the controversial aspects of marketing and more specifically advertising is the fact that they are aimed at the non-rational dimension of our minds. Even though we are several centuries into the Age of Reason, most of our behaviour is not rational and marketers know this very well. Advertising aims to show an idealised world that communicates the value consumers can create with a product.

Toulmin Analysis

To see what happens when you rationally analyse a television ad, such as this Garnier Mineral Deodorant clip we can use Toulmin Analysis, designed by influential philosopher Stephen Toulmin.1 In this model, every rational argument needs to possess a range of attributes. Using this model for the Garnier Mineral Deodorant clip we get:

  • Claim: Garnier Mineral Deodorant reduces perspiration for 48 hours.
  • Qualifier: None.
  • Rebuttal: None.
  • Data: “Preferred by 8/10 Australian women”.
  • Warrant: Mineralite reduces perspiration (implicit).
  • Backing: Not provided.

This quick Toulmin analysis shows that there are some key aspects missing to this clip to make it a rationally convincing argument. Advertisements will rarely mention a qualifier, other than the occasional: “individual results may vary”. Rebuttals are of course never to be seen in advertising, except when compelled by law: “Smoking kills”. Although the ad mentions that this product is preferred by 80% of Australian women, no evidence is provided to verify this claim.

Logical Fallacies in Advertising

The warrant and backing are the most important aspects of the argument. They are the link between the data and the claim if they are not valid, the argument collapses. In most advertising, the warrant is stated implicitly. In this case, the warrant is that Mineralite reduces perspiration. The ad does unfortunately not provide any backing for this claim and thus the argument to use Garnier disappears in a puff of logical smoke. Mineralite is a brand name for perlite, a volcanic glass with hydrating properties.

The aspects of this advertisement that truly convince consumers to purchase this product is not its logical structure—which can be considered a fallacy—but the imagery.

It is interesting to note that the German version of this ad makes the warrant explicit. It also uses the word ‘sweat’ while the Australian version is less explicit in its wording. The images show an ideal that the targeted consumers can identify with. Advertisers and politicians know that we are more easily persuaded by non-rational arguments and the Toulmin Analysis is a very effective way to point this out.


  1. Stephen Toulmin, The Uses of Argument (Cambridge University Press, 1958).

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