Many people rely on intuition when trading, betting a few times and thinking they are chosen by the heavens; losing a few times and blaming the market for unfairness. In fact, the difference isn't that complicated—people who understand probability and those who don't have completely different decision-making logic.

The "probability" we often talk about actually has several interpretations.

**The first is called classical probability**, which is the most intuitive. Developed by Laplace—assuming all possible outcomes of an event are equally likely. For example, rolling a die, with six faces equally probable, the probability of rolling an even number is 3/6=0.5. Similar to high sell and low buy in trading, with two directions of movement, but the actual market isn't that symmetrical.

**The second is called frequency probability**. The theory of Venn and Fisher—probability = the relative frequency of an event occurring in long-term repeated trials. This is closer to reality. If you want to develop a habit of waking up early, and check the past year's records—out of 365 days, you woke up at 6 am on 292 days—then your current success rate for waking up early is 0.8. Similarly, backtest your trading strategy; the historical win rate can roughly infer the future profit and loss expectations.

**The third is called subjective probability**, centered on Bayes' theorem. Here, probability isn't a fixed number but a belief that is continuously updated with new information. If you flip a coin on the street and get five consecutive heads, a normal person would suspect the coin has been tampered with. Similarly, if you encounter abnormal slippage repeatedly on a certain exchange, you need to update your risk assessment of that platform.

**The fourth is called propensity probability**, proposed by philosopher Popper—probability isn't due to human ignorance but is an inherent "physical property" of things. In quantum mechanics, a particle remains in an indeterminate state before observation; this uncertainty objectively exists. The crypto market is similar—certain trends are driven by deep underlying factors like capital flow, technical signals, and sentiment.

The key is, truly profitable traders use a combination of these probabilities—they don't bet on luck but infer win rates from historical data, continuously revise judgments with new information, and finally place bets based on "potential energy" and "mechanisms." Ordinary traders say, "I just feel it will go up," while experts say, "Historical data shows the probability is X, and the risk-reward ratio is Y." That's where the difference lies.