| Term | Definition | | Photosynthesis | The process by which plants take CO2 from the air (or bicarbonate in water) to build carbohydrates, releasing O2 in the process. There are several pathways of photosynthesis with different responses to atmospheric CO2 concentrations. |
| Placebo | A fake treatment that should have no effect outside the power of suggestion. Example: In drug trials, test patients may be given a pill containing the drug or a placebo, which resembles the drug (pill, injection, liquid) but doesn't contain the active ingredient. |
| Plutocrats | Wealthy individuals and corporate magnates - wield outsized influence over public discourse. Their funding networks shape think tanks, political campaigns, and media outlets that cast doubt on scientific consensus, particularly around climate change and public health. |
| Population | The entire group the researcher is studying. If the researcher cannot gather data from the population, studying large random samples taken from the population can be used to estimate how the population would respond. |
| Precession | The wobble over thousands of years of the tilt of the Earths axis with respect to the plane of the solar system. |
| Pretraining | Pretraining is the large-scale learning phase that gives an AI model broad knowledge before fine-tuning. LLMs are pretrained to predict the next token using a massive dataset that includes the whole public internet and any private, licensed, and synthetic data the developers can find or create. |
| Proof | A scientific proof generally refers to a high-level accumulation of evidence, experiments, and observations supporting a theory. It does not signify absolute 100% certainty. |
| Protein | Proteins are fundamental components of all living cells. Proteins are made up of one or more chains of amino acids, which are folded into a specific three-dimensional shape. They exhibit an enormous amount of chemical and structural diversity, enabling them to carry out an extraordinarily diverse range of biological functions. Proteins help us digest our food, fight infections, control body chemistry and in general, keep our bodies functioning smoothly. |
| Proxy | Something that represents something else. A proxy data source is an indirect source of data that scientists use when direct measurements are not available. For example, annual tree rings are a proxy for precipitation data. |
| Pseudoscience | Practices or beliefs that claim to be scientific but do not follow the scientific method, often characterized by unproven, unfalsifiable, or exaggerated claims. |
