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Toulmin logic

Stephen Toulmin developed a simple form of logic. The main idea behind Toulmin logic is to state a claim or proposition; provide evidence or a ground that supports the claim; connect the evidence supporting the claim with a warrant or qualifier. Take the following example: 

Looking at the image above, one could make the following claim or proposition: There is fire behind the mountain

However, taking the logic provided by Toulmin, we would need to revoke evidence or specific grounds that will support the claim. Hence, the follow up question would be — what’s the evidence or on what grounds do we claim that there is fire behind the mountain? 

The evidence or grounds would most likely be that we can see smoke coming from behind the mountain

However, both the claim and the evidence provided may need an additional warrant for the reader to be convinced of the argument. In some cases, these may be implicit, in other cases we would need to make them explicit. In scientific writing, we would prefer to make our arguments as explicit as possible, specifically when we are interpreting the evidence of our results in the discussion section. If we do not make the interpretations clear (linear), our audience will most likely fill in the blanks themselves.

As such, the bridge we provide between the claim and the evidence is referred to as the ground. The grounds (or bridge) for our claim there is fire behind the mountain would be where there is smoke there is fire or there is no smoke without a fire. 

Thus, we have completed the argument in a very straight linear fashion.

There is fire behind the mountain, as we can see from the evidence that there is smoke coming from behind the mountain based on the premise that there is no fire without smoke.

In our science writing, however, we may need to present not only one piece of evidence but we may present a few  grounding statements which support our claim. In addition, according to Toulmin logic, we may include a qualifier to our argument. The qualifier determines how certain we are about our support. Examples of qualifiers in this context are modals such as should, may, could, etc.

Toulmin logic is a basic structure and format that can help you get an idea how you want to organise your arguments. However, as with most of the suggestions we provide for your writing, there is no one answer that fits all. As such, we do suggest you to explore different types and structures of arguments. Remember that argument structures are not fixed and there is room for flexibility within all structures.