How would you differentiate between a scientist, an intellectual, and a rationalist?

Q: Are you a rationalist, Dr. Krishna?

Q: How would you differentiate between a scientist, an intellectual, and a rationalist?

Krishna: I am a scientist, not a mere rationalist.

Rationalism is a philosophical view that knowledge comes from reason and logic, while scientists use the scientific method to establish facts through experimentation and testing (scientific method):

• Rationalism: A philosophical view that knowledge comes from reason and logic, and that reason is the best test of knowledge. Rationalists believe that everything has a logic behind it, and that reality has logic.
• Scientific method: A process for establishing facts objectively through experimentation and testing. The scientific method involves making an observation, forming a hypothesis, making a prediction, conducting an experiment, and analyzing the results.
• Intellectualism: ability to think critically  about the world

Scientists are professionals who use the scientific method to conduct research and gather evidence to gain and share knowledge. They may make hypotheses, test them, and formulate conclusions based on the evidence. There is no place for opinions in science.

Rationalism is the practice or principle of basing opinions and actions on reason and knowledge rather than on religious belief or emotional response.

In a major philosophical debate during the Enlightenment,rationalism (sometimes here equated with innatism) was opposed to empiricism. On the one hand, the rationalists emphasized that knowledge is primarily innate and the intellect, the inner faculty of the human mind, can therefore directly grasp or derive logical truths; on the other hand, the empiricists emphasized that knowledge is not primarily innate and is best gained by careful observation of the physical world outside the mind, namely through sensory experiences. Rationalists asserted that certain principles exist in logic, mathematics, ethics, and metaphysics that are so fundamentally true that denying them causes one to fall into contradiction. The rationalists had such a high confidence in reason that empirical proof and physical evidence were regarded as unnecessary to ascertain certain truths – in other words, "there are significant ways in which our concepts and knowledge are gained independently of sense experience". (1)

An intellectual is a person who uses critical thinking and research to study, reflect, and propose solutions to societal problems. They are often educated and interested in complex ideas.

Other words for  intellectuals include genuine high grade expert, genius, and critical thinker.

Most scientists can be all of these.  

Rationalists need not be scientists because they need not go into experimental work to test and establish facts using scientific method. Rationalism can deal with any field, not just a scientific one.

Again intellectuals can belong to any field. They need not use scientific method to establish facts when they belong to other fields but can take them into consideration while coming to conclusions. 

Although they seem to tally in some ways, there is a lot of difference between us.

I am a scientist, not a mere rationalist and a critical thinker. Because apart from using reason, logic, and critical thinking, I also conduct experiments and use the scientific method to conduct research, and establish evidence based facts. I go further to show genuine evidence and that my thinking is on the right path. I don’t stop with just thinking.

Then I ask others to peer-review my work and falsify my thoughts. Others need not do this although they might sometimes consider criticism.

As my work is based on genuine evidence, other people can certainly use it to make things work in a practical and beneficial way. That certainty is the hall mark of science.

Scientists

Footnotes:

1. https://en.wikipedia.org/wiki/Rationalism