Note: This is not a detailed account of the tripartite theory of knowledge or the Gettier cases but is rather a brief overview of the two. My knowledge and research are not substantive by any means, so feel free to let me know if I have missed out on anything critical or misrepresented something. 

The questions of how we know what we know or how we deem what we know as "knowledge"  have formed a core part of epistemology - the philosophical branch concerned with the nature and origin of knowledge. More than that, these questions have found their way into several other disciplines and research fields, including effective altruism. 

The core principles of EA involve making decisions and taking actions based on the best available evidence and reasoning in order to do the most good. This directly ties into epistemology and the questions of how we know what we know, because effective altruists need to ensure that their knowledge about what actions are most effective is well-founded, true, and justified. 

The tripartite theory of knowledge was initially introduced by the ancient Greek philosopher Plato, and is now a fundamental idea in philosophy. The theory creates a framework of conditions that must be met in order for something to be classified as "knowledge", and for someone to truly "know" something.

Belief - Truth - Justification

The three conditions of the tripartite theory of knowledge are as follows: belief, truth, and justification. 

1. Belief: You must genuinely believe the proposition.
2. Truth: The proposition must correspond to reality.
3. Justification: There must be solid evidence or reasons supporting the belief.

To illustrate how these conditions lead us to the knowledge of something, I will be using an example in the context of effective altruism. For instance, suppose you believe that Charity A effectively reduces malaria in a specific region. To know this, the three criteria must be met. 

1. Belief: You must genuinely believe that Charity A effectively reduces malaria
2. Truth: This belief must correspond to reality - meaning that Charity A must actually be effective in reducing malaria
3. Justification: Your belief must be supported by solid evidence such as data from trials showing a significant reduction in malaria cases due to the intervention of the charity, independent evaluations, or expert health testimonies that can attest to the positive impact that the charity's work has had. 

For example, you might come across a reputable report stating that Charity A has reduced malaria incidence by 50% in the region over the past year. You also see data from health organizations corroborating these findings. Moreover, personal accounts from those in the affected areas might confirm the positive changes. With this evidence, your belief is not only true but also justified, fulfilling the tripartite theory's criteria. Thus, you can confidently claim to know that Charity A is effectively reducing malaria in the region - which also ensures that your support and donations are well-placed. 

According to the tripartite theory of knowledge, false beliefs or justifications do not constitute knowledge. For example, suppose you believe that Charity A effectively reduces malaria based on a report you read. If the data in the report were inaccurate or fabricated, your justification for believing in the charity's effectiveness would be false, meaning it does not count as knowledge. Similarly, if Charity A's interventions turned out to be ineffective despite your belief, this belief would not constitute knowledge, as genuine knowledge cannot be based on falsehoods.

Limitations of the Tripartite Theory of Knowledge 

Gettier Cases

While the tripartite theory of knowledge was widely accepted, the philosopher Edmund Gettier identified exceptions to the theory that a justified true belief always equates to knowledge, known as Gettier cases. A very common Gettier Case example is the stopped clock scenario. Suppose you look at a clock that shows 3 PM and form the belief that it is 3 PM. If the clock is actually stopped but coincidentally shows the correct time, your belief is true and justified, but it seems incorrect to say you "know" the time because the justification is flawed, but at the same time it is not necessarily false.

In addition, there can be further limitations identified from the tripartite theory of knowledge, a couple of which I have listed down below.

• Justification Adequacy - The theory does not specify what constitutes adequate justification, and hence the question of whether something counts as sufficient evidence or reason for a belief can be quite subjective. In turn, this may not necessarily be an accurate measure or universal standard for knowledge. 
• Reliance on Belief - The theory assumes that belief is a necessary component of knowledge. However, some argue that certain types of knowledge (for instance, skills like knowing how to ride a bike or cooking a dish) may not require an explicit belief.

I do feel that further limitations can be identified from the theory, so feel free to add to this list.