What is the difference between 'if' and 'assuming that' in conditional clauses?

The main difference between 'if' and 'assuming that' in conditional clauses lies in their usage and the level of certainty they convey.

1. Usage:
- 'If' is a commonly used conjunction in conditional clauses and is used to introduce a condition or a hypothetical situation. It is used to express a cause-and-effect relationship or to discuss possibilities.
Example: "If it rains, we will stay indoors."

- 'Assuming that' is also used in conditional clauses but is more commonly used to introduce a hypothetical situation or a premise that is taken for granted. It is often used to discuss assumptions or to set up a hypothetical scenario.
Example: "Assuming that he passes the exam, he will graduate next year."

2. Certainty:
- 'If' is generally used when the condition or outcome is uncertain or when there are multiple possibilities. It does not imply a high level of certainty.
Example: "If I win the lottery, I will buy a new car." (There is no certainty that the person will win the lottery.)

- 'Assuming that' implies a higher level of certainty and is used when the condition or premise is considered to be true or highly likely. It suggests that the condition is taken as a given or accepted for the sake of discussion.
Example: "Assuming that the weather is good, we can have a picnic." (The assumption is that the weather will be good.)

In summary, 'if' is used to introduce a condition or possibility with varying levels of certainty, while 'assuming that' is used to introduce a hypothetical situation or premise that is considered to be true or highly likely.